Spam Filtering And Why Your Email Goes Missing
We're not big fans of spam filtering. Almost all of the issues logged with us along the lines of “Someone sent me an email and it went missing”/“I sent an email and it never arrived” are related to spam filtering somewhere. These days, spam filtering is performed several times in the email delivery chain whether you like it or not; it's not just the Junk Email folder in your mail client.
Virtually every time a piece of email is processed as it travels across the Internet, a judgement is made about its content, who it's to, who it's from and the enclosed links and attachments. And because IT managers and ISPs have an over-developed anathema of spam, often the tolerance for what constitutes real email is tuned too low, and hence the prevalence of “false positives” — and your missing email.
It's becoming a real problem, because the lost productivity chasing missing emails is now out of proportion with that arising from just deleting junk when it arrives.
In 2012 there was an interesting real-world example where some missing email has caused more complicated legal problems: AdelaideNow: Bun fight over fast food site.
And, slowly, email is becoming less reliable just as it becomes more ubiquitious and business-critical. People assume an email will arrive, and yet, frequently, it doesn't. And to complicate matters, an email pathway which was working yesterday may fail today because some settings have been changed along the way, or a mistake is made with various types of filtering.
The moral of the story is that, since users can't control the amount of filtering that is applied to their email, and spam-filtering as a whole has become a massive beast that virtually nobody has the will or ability to control, you can never assume a message you send will arrive. So if you send something important, and you don't receive some sort of confirmation that it arrived (such as a reply), your best bet is to call the recipient and check that they have it — because you don't want to find out six weeks later that some time-critical correspondence vanished.
Phoning people to check they got an email? Yes, it's 1995 again.