figuring out the gmail spam filters

So I'm working on a web application, and today I was trying to send invites out to some users. Turns out that they were going into the gmail spam filter.

I made sure that my RDNS (Reverse DNS) was set up correctly, and then I checked the email headers to ensure that gmail didn't suspect my ISP's IP address as a spammer IP.

A friend suggested that it might have something to do with the content of my emails, and not the body.

So I started playing around and, sure enough, that was it. After several emails I realized that it had to do with the link I was sending in the email. At first I thought that it might have to do with the length of the link (and an MD5-encoded token in the params).

After several tests I figured out exactly what trips it: If I send email from a foo.com server (hostname = foo.com, DNS and RDNS consistent with foo.com) with a signup link for foo.com, then that sends the mail to spam. If, on the other hand, I send email from a bar.com server with a link to foo.com, then the email makes it through the spam filter.

That seems so non-intuitive to me. It seems more shady for an email from bar.com to have a link to foo.com in it.

Anyways, I've got a temporary work-around (I think?), but I still don't know the 'right' way do this.

music for the soul

At most points in my life, I've listened to, sang, played, and loved music that 'spoke' to me. I think most people know what I'm talking about.

Sadly, there have been some points (more so recently) when I just haven't been able to find music that speaks to me. Much of my music collection just doesn't do it for me anymore. Even classic evergreens like U2 and Bob Dylan - which usually always have something to say to me - just fall on my ears but don't penetrate any deeper.

Those who know my general music taste; feel free to recommend me some new music.