It was because of prittii! She was experimenting, after seeing someone write an entry with lots of exclamation marks which stretched out the main page a little. Long entries with no spaces in apparently do mess up the main page. Most people's long entries have spaces in, which enable the next word to go onto a new line. But a long entry with no spaces causes the main page to widen.
This was a bug that was fixed at one point, but I guess there are problems with it again. Prittii was making the Bloop powerz aware! ;D Such a conscientious little bug spotter she is, yo! ;D Wonder if it's fixed now.