Just this morning, a spam filter rejected and sent back one of my emails with the following text:
Heuristic analysis has classified your e-Mail as spam and delivery has been refused. We apologize if your message was misinterpreted. Please check your entire message for any restricted content and then attempt a resend. You may also request addition to our list of pre-approved senders.
"Heuristic analysis" was probably an overstatement. It was probably just looking for keywords. But what could I have written in my email about scheduling a business meeting that would have triggered the rejection? Well, I am relatively certain that the issue is this.... In my email signature (and, in this case, the body too) I have a shortened link (is.gd) to my Google calendar so that the recipient can see when I am free. Personally, I thought this was a great idea because I work with clients who use Exchange or other groupware to schedule meetings when everyone is free. This technique allows the meeting organizer visibility into my calendar without my needing to join their calendaring system. I used a shortener because the link is really long. I use plain text emails so the length of the URL matters to me.
I still think exposing my calendar is a good idea so I figured out a work around. Google allows you to embed a calendar in another page so I just embedded it in page on http://www.contenthere.net that can easily be linked in an email. I am hoping this will lead to a drastic reduction in spam accusations.