My post above contained a tracking beacon which was logging IPs & useragents; the link in my post went to a free hosting provider which I set up using a manner of techniques to log information about visitors (using JavaScript, PHP, and an embedded flash player which was requesting a video from my server), and then after a few seconds forwarded you to a legit blog post.
Fascinating! How can you possibly embed such code in a forum post? Surely this indicates a serious bug in SMF, the forum software?One of the IP addresses you mention is mine, and I'm not joe23. Thanks for doing the xx.xx'ing - I'd hate to have a bunch of you guys suddenly trying to hack my box!
Here's a web bug:
(it can be a blank image too)
Here's where you can see email notifications of everybody that viewed the image, along with their IP address, reverse domain name, and browser user agent: http://spypig.mailinator.com/
Update: spypig.com only sends information about the first five views, so the fun was over pretty quick.
I'll leave this here to freak you out instead: