According to someone who tipped me off through PMs, it seems that someone on this forum has been trying to log IPs with IP logging (WW3). Looking at the source code of some of his posts in the test thread (from the sounds of it this isn't the only topic he's done it in), things like this appear:
<img alt="" data-cke-saved-src="http://iplogger.com/1uPT5.gif" src="http://iplogger.com/1uPT5.gif">
These are within what appear to otherwise be completely blank posts. Thoughts on how to proceed?