Alan recently posted a thread directly selling a product he developed. ExPo has a rule that vendors and manufacturers have to be supporting sponsors of the site to post offers. So his thread was taken down, and Alan was informed of the rule. Alan didn't like this, and announced he was leaving ExPo. Sounds like he may have deleted his other posts on the way out.
Members of ExPo have the ability to delete posts they make. If a member starts a thread, then deleting the first post will cause the entire thread to disappear. This ability is controversial, since others who have posted in the thread will lose their posts as well.
When the moderators have polled the ExPo community if this ability to delete should be changed, no consensus has emerged.