In reply to Gordon Stainforth:
Here's my speculation. I wouldn't be surprised if server got down, they tried to back it up and something went wrong (time zones, algorithms to find the newest thread, database mismatch, etc.). I can't imagine how it was programming error and I don't think it has anything to do with people (well, apart from creating a bug in the system!). I am not a WEB developer, but that sounds more feasible than that someone is messing around with UKC.
If you are interested in any particular topic (or want to see if someone replied to you), just add it to your topics and track them by "My Topics". It looks like the bug affects that list as well, though.