My recently erratic world of the Gmail spam filter

Let’s start with a brief history of my investment-led fight against the perils of spam and my never-ending love of SMTP.

We were investors in Postini and my partner Ryan sat on the board. It transformed my life – with one minor change of an MX record some time in 2002 all the spam in my inbox disappeared. Well — it disappeared before it got to my inbox. Or even my server. The awesomeness of Postini was that it was the first cloud-based email anti-spam solution. And it was a beautiful thing that Google acquired in 2007 for $625 million.

One of the benefits of our investment in Postini is a lifelong friendship with Scott Petry. Scott is a cofounder of Authentic8, which we are also investors in. Scott also sits on the board of Return Path, which is run by another lifelong friend Matt Blumberg.

Scott worked at Google for there years after the transaction for Dave Girouard (who used to run all of enterprise for Google and now is chief executive of Upstart and on the board of Yesware with me) integrating Postini into all of Gmail’s infrastructure. We continued to use Postini as our spam filter (in front of Gmail) until Google transitioned all of Postini into the Google apps service.

You get the picture. There’s a nice thread through all of this SMTP, email deliverability, and anti-spam stuff in my world, both in investment and relationships. So I generally don’t think much about spam since in the past it just disappeared — or, well, never appeared in the first place.

When I came home from my one month sabbatical in Bora Bora, I archived all the 3200+ emails in my inbox. If you missed my vacation reminder during that time, it said:

I’m on sabbatical and completely off the grid until 12/8/14.

I will not be reading this email. When I return, I’m archiving everything and starting with an empty inbox.

If this is urgent and needs to be dealt with by someone before 12/8, please send it to my assistant Mary (mary@foundrygroup.com). She’ll make sure it gets to the right person.

If you want me to see it, please send it again after 12/8.

On Thursday, Dec. 4, Amy decided to scan through her email, so I went to the business center at the St. Regis in Bora Bora with her and did the same. I simply started at the top and “read / archived” each of the around 3,300 emails (using the “[” shortcut). I’m a fast reader, so I skimmed the emails I cared about. Mostly I just played a video game with the [ key. I might have had a tropical drink while I was doing this.

I didn’t respond to anything and just ran this drill again early Monday morning to finish up. I then turned off my vacation reminder, had Inbox Zero, and got started again.

Yesterday, I had a weird feeling that I’d missed something that I heard about in another email thread. I was procrastinating from working on the final edits to my new book Startup Opportunities (yes — I’m doing that some more right now, but I’ve got a nice empty day in front of me) so I randomly checked my Spam folder in Gmail. I never, never, never do this, so I was surprised when on the first page I saw a legitimate email. I opened it, clicked on Not Spam, and scrolled to the next page, where I saw another one. And another one.

I had 5,500 messages in my spam folder since I got back on Dec. 8. I went through all of them — it only took about 10 minutes. I found 39 legitimate emails. Not notifications, not email newsletters — but real emails sent to me by people I often get emails from. Here’s a screenshot of the legit ones.

I did my dutiful work and hit “Not Spam” on all of them. I was perplexed and talked to my friends at Return Path who gave me some feedback.

This morning, I had 433 messages in my Spam folder. This time, they all looked like they should.

I’m hoping that this was only a temporary glitch in the matrix. However, I’ll be checking my Gmail spam folder on a daily basis for a while. Boo.

This story originally appeared on Brad Feld. Copyright 2014