spodefly, I'm obviously not the OP, but I've done it once or twice myself. Both times it was because I did a search to avoid posting a dupe, found a related thread and posted to it without realizing that it was fossilized. I've always assumed that most of these get bumped up the same way.
They joined and then made their first post to this thread, and it was the first post to the thread in 2 years. I have seen that happen before a time or two and wondered about it. I can see joining and jumping on one of the existing threads obviously, but it seemed like they joined just for this thread.
Just one of those curiosity sort of things us cat people are known for.