Email Deliverability-palooza: The Plot Thickens

In March we wrote about our first attempt to find out if certain broadcast email clients delivered email better than others (read the original post here). When those results proved inconclusive—and a little mysterious—we promised a second try. Here’s what we knew going into the revised study:

When your organization sends out bulk email, you have to accept the fact that not all messages will be delivered. Many different factors make this a reality. Your supporters may supply inaccurate or false email addresses, causing messages to bounce. Or your constituents’ email clients might look at your campaign and decide it’s spam, catching the email in a filter before it reaches its destination. To some extent, that’s the nature of the beast. But we wondered if that beast could be tamed by better understanding what causes those undeliverables.

There are many different reasons for emails to get caught by spam filters. They may be flagged as spam based on keywords in the body of the message, like “pharmaceuticals” or “Nigerian royalty.” They may lack a link for recipients to opt out of your list, which should be included in every message. Or, since most organizations prefer to send out HTML-formatted emails because of the visual appeal, yours might get flagged if you don’t also have a plain-text version available.

Mail server administrators generally like to keep their systems free of unsolicited messages, for obvious reasons. One of the ways they do this is by subscribing to blacklists (or block lists) run by organizations that create a database of IP addresses known to send spam. When email is sent by a server, it can be tracked back to that server by an IP address, and these lists catalogue which IP addresses are recommended to be turned away. In practice, this means that incoming emails are checked by the server against this database, and if they come from a “bad” source they’re rejected. Domains get put on these lists when enough people complain, or “flag” messages that originate from them. It’s relatively difficult to get off of one of these lists, and it can take some time.

Due to the sheer volume of email put out by broadcast email tools, it’s not hard to imagine that these services have to contend with blacklists on a regular basis. This brings up the problem of guilt by association. When you’re using a broadcast email tool, you’re sharing an email server with other organizations and businesses. Their bad behavior has the potential to negatively influence your email deliverability.

Given the hassle of getting off a blacklist, prevention is the best medicine when it comes to spam. Broadcast email tools usually try to prevent bad sending practices. You may be required to send yourself test versions of every email, or each email may be reviewed by a member of the vendor’s staff. Other tools have a voluntary “spam checker” tool that lets you analyze each message for problems that may increase its potential for being caught in a filter.

Next week, we’ll share the results of our study. Check back here on Monday to see what we learned.