Mario Marlisa - Return Path
Mario Marlisa – Return Path

In this interview, Mario Marlisa, Channel Relations EMEA at Return Path, shares his views on the email deliverability matter. In case you don’t know what the company does: Return Path helps commercial email senders get more email delivered to the inbox.

Return Path provides email deliverability tools and professional services giving senders the insight and resources to achieve higher inbox placement rates and improve email response and ROI across the customer life cycle for their email marketing efforts.

Return Path also runs the Internet’s most widely used third-party whitelist, the Return Path Certification Program and invented the Sender Score, an email reputation measure based on data contributed by ISPs and receivers of large volume email into the Return Path Reputation Network.

The keys to reach the inbox: permission, engagement, frequency and reputation

What are the main elements of an email that ensure it will be delivered?

Mario Marlisa: “It depends if you mean delivered or delivered to the inbox because there is a huge difference. Many people talk about delivery but only if emails actually reach the inbox can they be responded to by the recipients. I can’t emphasise this enough. There is in my experience a lot of confusion around these two ‘different’ definitions and marketers should be focused on the inbox, because only there a message can be clicked, interacted with and responded to”.

What are these main elements to reach the inbox? Mario sums up four elements: permission, engagement, frequency and reputation. Let’s tackle them one by one.


Mario Marlisa: Know where each email address originated and make sure the subscriber provided clear consent to receive email from you. For instance, if you work with a third party, perform some due diligence beforehand to understand where and how they obtained their email addresses, and if they properly disclosed how those email addresses would be used.


So, in case you would have any doubts about this: permission still rules in email marketing, regarding deliverability too. Then comes engagement.

Mario Marlisa: Perform regular list hygiene. Your goal is to maintain an active, healthy file so carefully track the activity level of your subscribers. Are your subscribers responding to your offers? If so, how often? The more engaged your subscribers are the more likely you are to drive response. Consequently, inactive subscribers tend to complain more, which can drive down your inbox placement rates. Make sure you track engagement metrics to be sure you only send email subscribers want to read.

Engagement. It’s a word that comes back in nearly every post I do regarding email marketing (and social media marketing), and it’s important in email deliverability too.


Mario Marlisa: Sending less is more. Contrary to popular belief, it’s not about sending more email (editor’s note: not everyone agrees as you can read here). In fact, you should send less mail that is more relevant to your subscribers. Relevance drives engagement, which drives response so concentrate on sending only email that matters.


And, finally a word on (sender) reputation, another email deliverability keyword.

Mario Marlisa: ISPs determine inbox placement based on the reputation of the sender. Therefore, following best practices that reduce complaint rate, unknown user rates, and spam traps hits is an email marketing imperative.

The increasing role of engagement

So, let me repeat the four main elements: permission, engagement, frequency and reputation. Have you noticed the word ‘relevance’? It’s something we talk about often, among others in the context of content. Notice how Mario answered that “relevance drives engagement”.

Now, let’s take engagement a bit further. I asked Mario what other methods ISPs are using or testing these days besides content filtering. As I wrote before one of these methods seems to be checking the interactions recipients have with the emails, in the US at least.

Mario Marlisa: There has been talk about engagement, but currently there are only a few US ISPs that look at some type of engagement. And there are no ‘set’ rules – each receiver currently takes a different view.

The question that arises immediately is what these different views are. Here are some examples Mario gave:

  • Yahoo looks at mailbox actions like click, open and time in the inbox before mail is deleted.
  • Microsoft uses their panel data to help determine inbox placement.
  • Gmail considers the “This Is Spam” and “This Is Not Spam” the biggest factor in how they view engagement.

The good, the bad and the whitelisted

However, engagement does not seem to be the main topic at ISPs, certainly in Europe.

Mario Marlisa:  Most ISPs are not in a position to track these types of metrics right now, so I don’t see many European ISPs going this route this year. Most will start looking at authentication and domain reputation tracking, though.

Have you noticed other changes in the way ISPs determine if an email is OK? And what about corporate and individual solutions to keep the inblox ‘clean’?

Mario Marlisa: ISPs have to constantly change the way they filter email and gauge if the email is legitimate or not. However, there has been a shift from weeding out the bad to finding the good.

As such, email marketers will have to really shift their focus on following best practices, particularly authentication, whitelisting and engagement. With phishing and spoofing becoming more prevalent, all marketers (not just financial institutions and social networks) will have to authenticate their mail. Secondly, more ISPs are using trusted whitelists to identify good mailers. Return Path offers the Return Path Certification program which is used by leading Spam filtering solutions like Cloudmark, Spam Assassin and ISPs including Hotmail, Yahoo!, KPN and some are looking at deeper engagement metrics that go beyond opens, clicks and conversions to determine inbox placement such as the number of emails that are voted “not spam”. So, it’s no longer just one criterion, but many because the majority of emails that ISPs deal with is bad mail. By working with them, we can bring a unique level of transparency to marketers from an area of the industry that is constantly changing to respond to ongoing threats from spammers.

The role of list hygiene, content and relevance

What should companies with large lists look at from a deliverability viewpoint?

Mario Marlisa: Big companies with large lists should focus on devising strong segmentation strategies. List hygiene is incredibly important: make sure to not only regularly remove bounced email addresses, but also look at who is engaged. If you have subscribers that never open, click or buy your offerings, it may not be worth keeping them on your list? You want a healthy, active file. Check in with your subscribers. Ask them what they like and don’t like and remember to focus on three key factors – permission, engagement and frequency.

One of the effects of the recession is that email marketers take more care about the content, relevance and efficiency of their mails according to Forrester.  Have you noticed any impact of these efforts regarding deliverability?

Mario Marlisa: This is great news (if it’s true). Actually, we see too little targeting and segmentation. However, Forrester also reports that when marketers DO improve the relevancy of their messages by using segmentation and targeting and custom content, they see much improved response rates. When subscribers are satisfied and enjoy the messages, they are less likely to complain. Low complaint rates are the single biggest factor in inbox placement – not content, bounce rates, or the ESP you use. It’s all about keeping subscribers engaged. Higher response and higher inbox deliverability go hand in hand”.

The increase of the number of emails and its impact on deliverability

Forrester also found that, due to the recession, more emails are being sent. Do you see the same and what’s the effect on email deliverability?

Mario Marlisa: This seems to be true. Not only are marketers sending more frequently as email replaces higher priced direct marketing strategies like postal mail and tele-marketing, but more businesses are testing the medium. It’s a very inexpensive channel if you do it well. However, if you don’t take care to build an active list, and send relevant, well timed messages, or if you abuse the permission granted by sending more than expected – then your sender reputation will suffer, and you will find most of your messages get bulked or filtered at the gate. In that case, bad email marketing will cost you a fortune.

Research also predicts a rise of the number of emails sent for the following years. Thoughts?

Mario Marlisa: If there will be a massive rise in the number of emails sent, consider for a moment the landscape with increased numbers of spam (and this has increased massively year over year). This poses challenges for senders (marketers) to get delivered to the inbox and poses challenges for receivers to filter the massive amount of incoming email. Overall receivers will need more help identifying and filtering the good or wanted email and stopping the email that is not wanted. One thing is clear to me in my role and my time with Return Path – deliverability is not getting any easier, the landscape is constantly shifting and predicted volume increases are, in my opinion, set to make that harder. However, Return Path is poised to respond to these challenges and help marketers effectively navigate through these changes and differentiate themselves from the spammers of the world.

The integration of social media and email marketing

What are your thoughts on the integration of email, social and other channels in function of the customer who is one, a topic we feel strong about?

Mario Marlisa: Social networks are run on email and by this, I mean that the social networking subscribers’ email address always provides the unique identifier. This is important, especially when you think about transactional mail like password confirmations and marketing email to drive subscriptions and engagement within the network.  For email marketers, this is both good and bad. The good news is that more subscribers will use the inbox as a gateway to their social network, and that means they spend more time in the inbox and check more frequently.  The bad news is that there are more messages from the social network, and that competes for time and attention. So the net effect is that it raises the bar for email marketers to create emails that stand out from the inbox clutter. Every message must break through – be very relevant and be of high value. Getting both the content and contact strategy right is the key to success in 2010 and beyond.

The competition for the time and attention of people online: again the answer is relevance. Will there be a negative impact on email or will email be strengthened by integrating it with social media? In the end, it doesn’t matter.

What matters is connecting with people and customers the way they want.