Email Marketing

To prevent spam and malicious emails from reaching your inbox, email service providers filter out and block emails from suspicious IP addresses. You’re fresh new IP address rolled out in your Sender Authentication Package with Salesforce Marketing Cloud is suspicious in the eyes of most inboxes, and to protect their users most providers take a “guilty until proven innocent” approach to new IPs, So an IP Wamp-ip activity is needed to prove that you are a safe sender.

To oversimplify it, IP Warm-up (or IP Ramp-up) is the process of “getting email inbox providers to trust you”. It’s a necessary task to ensure your emails make it to your customers inboxes and don’t get flagged as spam.

Warming up your new Salesforce Marketing Cloud Email Sending IP can be a daunting task for some businesses since there is very little margin for error, so here are some quick ways to assess your subscriber database, plan a successful IP Warm-up Strategy, and reduce the impact to your business during this process.

Understand your database

Run a report on your subscribers’ email addresses to see what domains they use. Some enterprise marketing systems have this feature built in; however you can also run a quick SQL query if needed, for example:

	RIGHT(subs.EmailAddress, LENGTH(subs.EmailAddress)-INSTR(subs.EmailAddress, '@')) as 'Domain'
	,COUNT(*) as 'Count'
FROM [mySubscribers] subs
GROUP BY RIGHT(subs.EmailAddress, LENGTH(subs.EmailAddress)-INSTR(subs.EmailAddress, '@'))

The above SQL will strip the email username’s off every email address – leaving just the domain sections – and then count how many email addressed had that domain. Large public email providers like Gmail and Hotmail will top the counts in most circumstances. By itself this is already a really useful data set, however one more thing needs to be done before we can use this information for planning out IP Warm-up Strategy.

Some email providers operate from multiple addresses, and we need to group any related domains together. For example, Microsoft owns,, and – to name a few – so it’s important to group these all as “Microsoft Domains”.

You’ll also find that 95% of the unique domains will only have a handful of subscribers each. For all the domains with under 1000 subscribers you can group them into a segment called “other”.

IP Warm-Up: Strategy Overview

The goal of your IP Warm-up strategy is to gradually increase the reputation of your email sending IP address so that you can send an email to your entire database at once.

One of the ways Email service providers protect their users from spam is by limiting the volume of emails coming from an IP address over a 24 hour period. For a fresh new IP address this is typically around 20,000 emails per 24 hour period, however some providers are more restrictive and only allow 10’000 or 5’000 per day!

Additionally, inbox providers are watching how your subscribers interact with your emails; do they open, click, or mark as spam? Sending IP addresses that frequently get ignored or marked as spam will find themselves relegated to the junk box very quickly!

Knowing these daily safe limits and key indicators that the inbox providers are looking for, you can build a sending schedule that demonstrates how safe and valuable your emails are – ensuring you get that VIP inbox placement from the spam filters.

IP Warm-Up: Daily Limits

The Internet is littered with Daily (and Hourly) volume recommendations, ranging from <100 right up to 20,000 from day 1. In truth, there isn’t a direct science here since each provider keeps their spam filter rules a tightly guarded secret. With that in mind, here are a few resources you can check out to get more information about the various recommended daily limits.

In my experience, starting with around 5,000 per domain-group per 24 hour period, then doubling it every 7 days is a safe warm-up strategy. Note that Microsoft and Gmail have notoriously sensitive spam filters, so starting at 2,000 (or even 500) per day for these providers would be a very risk-adverse strategy.

The “Other” segment (made up of all the smaller domains with only a few emails addresses each) can be sent to 100% from day 1. This group doesn’t need to be IP Warmed-up since each domain has a volume that is too small to trigger any send volume issues.

Doubling the daily limits each week will soon escalate to large numbers for each domain very quickly, and for some smaller domains you will quickly run out of subscribers to send to. Once you’ve met or surpassed the daily requirement for a domain, you can remove them from you Warm-up segmentation process and just send to them normally, you don’t need to send to the same group multiple times to fulfil the sending thresholds.

IP Warm-Up: Email Engagement

After your email sending volume, the next most important element of your IP Warm-Up strategy is ensuring your subscribers are engaging positively with your first few emails. The content of your emails is a key consideration of course, however there is one strategy you can use to improve overall engagement from the beginning – send to your best subscribers first!

Ordering your IP Warm-up email segments from highest to lowest engagement (recent Clicks & Opens) is the best way to ensure your first few sends get really strong open and click rates! When I’m working on a warm-up strategy, I use the following formulae in Salesforce Marketing Cloud to sort subscribers:

 ,(DATEDIFF(day, DateAdd(dd,-91,GETDATE()),Last90Click) * Count90Click * 5) + (DATEDIFF(day, DateAdd(dd,-91,GETDATE()),Last90Open) * Count90Open) as 'Score'
 FROM ent._subscribers s
     ,MAX(EventDate) as 'Last90Open'
     ,Count() as 'Count90Open'
     FROM ent._Open
     WHERE EventDate > DateAdd(dd,-90,GETDATE())
     GROUP BY Subscriberkey ) o ON o.Subscriberkey = s.Subscriberkey
     ,MAX(EventDate) as 'Last90Click'
     ,Count() as 'Count90Click'
     FROM ent._Click
     WHERE EventDate > DateAdd(dd,-90,GETDATE())
     GROUP BY Subscriberkey
 ) c ON c.Subscriberkey = s.Subscriberkey

The SQL above produces a list containing every “EmailAddress” and a “Score” based on their clicks and opens over the last 90 days; with high scores indicating higher engagement. Records that don’t have a score next to them have no open or clicks in the last 90 days.

Remember that the goal of the IP Warm-up is to show the email service providers that you send high-quality emails that your subscribers want to see in their inboxes. For this reason you need to focus on subscribers that have a high propensity to open and click your emails – the metrics that count in the inbox. Don’t make the mistake of including high purchase value or membership duration figures into your engagement calculations; which these may be your “high value” subscribers, they are not the subscribers you need for this activity.

IP Warm-Up: Example

Below is an IP Warm-up Strategy example for a Retail (B2C) customer who sends 1 newsletter each week to their whole database. Firstly, the subscriber database is reviewed and grouped into Domains and Engagements.

Example of a database containing 767,436 Subscribers grouped into 8 Warm-Up Domains, showing recent engagement scores

From the above, we can see that a large majority of subscriber emails belong to Gmail and Hotmail, however almost 1/3 also belong to miscellaneous addresses grouped into “Other”.

Next, we can plan out how many emails can be sent each day, remembering to keep under the daily limit for each domain group. For this example I’ve used 5,000 for each domain and included a 5-day sending schedule – however I recommend selecting a starting volume and send schedule that is inline with your research and risk tolerance.

Looking at the above sheets, we can see that each week we are increasing in daily send volume, and by Week 3 there are already 3 domain groups that we can sent to completely in 1 day, with 3 more that would be fully sendable by Week 4.

The key insight that sits behind this sheet is that higher engaging subscribers are sent to ahead of lower engaging subscribers. This means that even though by Week 3 the “Yahoo, Telstra and TPG” domain groups are not being 100% sent to on 1 day, their “12229, 15117 and 12977” engaged subscriber populations are being sent on 1 day!

So even though the email hasn’t been sent to everyone, the subscribers who were most likely to Open and Click the email have being sent to, meaning your email campaign will still get a good volume of opens and click; thus reducing the business impact of the IP Warm-up!


An IP Warm-up is like a first date with the inbox providers; you only really get one chance to make a good impression (and it’s very difficult to get a second date if the first one didn’t go so well) – however if you put your best foot (subscribers) forward and follow some basic rules, it can result in a long lasting relationship!

Like all first dates, a bit of thought and preparation will go a long way, and after a while you’ll see there’s really nothing to be scared of. However if you think you need a wing-person to help you through the process, I’ve personally had some great experiences with the team at Validity (Formally Return Path), they’ve got some great resources and blogs to help navigate the email & deliverability landscape!

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Re-Engagement (re-activation, win-back, lapsed subscribers, dormant, etc) Campaigns are a core feature of every good customer marketing strategy, and while the immediate goal of these campaigns is well understood – to retain keep existing customers engaged – the true benefits of these targeted and automated communications is often lost on non-CRM marketers.

It’s time to talk in detail about one of the highest performing campaigns in an email marketers toolkit.

The benefits of a Re-Engagement Journey

Re-Engagement is cheaper than Re-Acquisition

Most companies know their allowable cost per acquisition – the cost they are willing to spend to acquire a new customer based on their predicted lifetime value. Most of the time the lions share of these costs come from above the line campaign spend in display, social, search, and other paid media channels.
Reinvesting this cost as a voucher to a lapsing customer via a re-engagement journey can significantly reduce media spend to re-acquire them later down the track. Re-Engagement vouchers have the added benefit of being a soft/internal cost to your business; meaning they only cost if they are being used, which also means they are working!

Reduce Subscriber Churn

Your churn rate isn’t simply the number of subscribers who click unsubscribe – it’s also all the subscribers who stop opening your emails! While these 2 subscriber states are functionally the same for your business – your emails are not being seen by customers – they are materially different for your database health and operating costs. Sending emails to customers who are never going to open them is a waste of your time, money and reputation (more on that shortly).
You can reduce churn by detecting lessening engagement and reaching out with a non-sales message.

Improve Subscriber Database Health

Sometimes your subscribers will become disengaged and there’s nothing you can do to prevent it – they no longer need to be affiliated with your brand – however they won’t say it to your face (your unsubscribe page). The best thing you can do is to let them go.
If a subscriber fails to re-engage during a win-back campaign, unsubscribe them. Tell them why they are being unsubscribed and how they can subscriber again in the future. Removing these records from your active database will decrease your send volumes/costs, and artificially improve your email open rates.

Improve Domain Health & Reputation

One of the lesser known benefits of a Re-Engagement Campaign is the impact it has to your sending IP address. Inbox providers are watching your sends; they review how many of your emails bounce, don’t get opened or are flagged as spam! Inbox providers are known for requisitioning abandoned inboxes and converting them into “spam traps”; inboxes that silently connect the addresses of senders who don’t adhere to good email database principals.
Your email domain reputation is affected negatively by disengaged subscribers and spam traps, and positively by subscribers who regularly engage with your emails. Identifying and removing disengaged subscribers can help keep your emails away from the junk folder.

What a good Re-Engagement Journey should have

A clear objective & measures of success

Although your Re-Engagement Journey is different to your standard marketing sends – it’s performance should not be measured or treated differently. Define what you consider engagement (open, click, add to cart, purchase, etc) and report on it’s performance to ensure ongoing success. Don’t be afraid to identify “removing disengaged subscribers” as an objective, as we covered above, this will benefit your IP Reputation.

Point of difference from your standard sends

Subscribers should know your Re-Engagement emails are different from the moment they see them in their inbox. The subject line should be short and clear, the email content should be clean and to the point.
In some cases this can be enough to get your email placed in the inbox rather than the promotion/spam folder for some subscribers!

Clear engagement message and actions

Re-Engagement emails should have a clear objective – don’t muddy the message with sales or product information – keep the focus on their continued engagement with your brand. Remove detracting messages banners and use simple Call to Action devices like buttons to identify what you want them to do with the email.

Give lapsing subscribers a choice

Black and white messaging will work on some lapsing subscribers; however sometimes “now is just not the right time”, and an in-between option could have retained a valuable future customer. Enter the Snooze option.
Giving subscribers the option to “snooze” emails for a duration of time is the easiest way to respect their changing communication preferences. Customers who use this option will be in a very particular mind-set; they want to deal with you again in the future, just not right now.
Use this information to your advantage. Design an “awaken” campaign at the completion of their snooze duration; welcome them back to the brand or invite them to snooze a little longer – we’ve all been there…

Keep testing and improving the Journey

Ensure the messaging in your re-engagement emails is performing by splitting all eligible subscribers into 3 groups and conducting an “ABC” test:

  • 70% receives the primary “A” version of the email.
  • 20% receives the testing “B” version of the email.
  • 10% is held as a control group “C” to measure email performance.

Building an ABC testing methodology into your journeys gives you the flexibility to create an ongoing testing process to validate hypothesis and business requests. The 70|20|10 split is relatively safe as the majority of your disengaging subscribers will receive the primary version, however there is enough statistical significance in the remaining groups to prove any test case you try.

Log and Record everything

Depending on your Re-Engagement Journey entry conditions, you may have subscribers who enter the activity multiple times per year! Keep a record of every subscriber who goes through your re-engagement activities and use it to report on long-term subscriber loyalty. The insights gained from viewing long-term subscriber engagement may help to identify problems in your on-boarding or always-on marketing strategy.

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