Deliverability – How client side filtering affects your emails and what to do about it

Tom Corbett

Marketers need to ensure what they’re sending is not being flagged as spam

This post is the second in a series on email deliverability by Tom Corbett.

In my previous post I introduced the basics of deliverability and its importance to email marketers.

In order for campaigns to be successful, marketers need to ensure that what they’re sending and the ways they send them are not being flagged as spam.

With this in mind we need to understand what happens after you click send.

Typically we don’t tend to care much about the journey an email takes – but it’s important to understand what has happened when it goes wrong.  Emails often feel instantaneous but the reality is that the average email goes on a long journey through many different filtering systems before arriving in an inbox.

All Internet Service Providers (ISP) have developed different filtering methods as a way of offering unique customer experiences to customer inboxes.  They all offer a form of global level blocking which makes a big difference in the world of email spam.

Now spam (spam, spam, spam, spam…)  is often a word that  is synonymous with annoying people. No one likes spam. Marketers shouldn’t be sending it because people do not like receiving irrelevant comms.

However, not only is it annoying and damaging to the customer experience for an individual, it is also potentially quite dangerous because not all spam is the result of ‘innocent’ unsophisticated marketing.

Malware is hugely profitable for scammers and costly to the individuals who fall foul of them. 70% of mail sent globally is considered spam and these filters drastically reduce the volume coming to your inbox. But everyone’s interpretation of what they consider to be spam is different. A saying I like is ‘one person’s spam is another man’s ham’. As a result, local level blocking has given the recipient the power to take control of their inbox.


The importance of humanisation in email communication is more and more important and making your email wanted is the key to a successful mail programme.

Gmail recently updated their Gmail android app to allow customers to have further control of their mailbox on their personal devices. Blocking a sender means all future mailings are instantly moved to the spam folder.

This means you need to ensure your recipients actually want to receive your messages. This means personalisation and relevance. What is there to lose?  By providing a more relevant and positive customer experience you’re putting your customer at the centre of your marketing and they’ll reward you for it.

Experian Marketing Services is a leading global provider of consumer insights, targeting, data quality and cross-channel marketing. We help organisations intelligently interact with today’s empowered and hyper-connected consumers.

By helping marketers identify their best customers, find more of them, and then coordinate seamless and intelligent interactions across the most appropriate channels, Experian Marketing Services’ clients can deepen customer loyalty, strengthen brand advocacy and maximise profits.