I've said it before and it looks like I'll have to say it again, PLEASE auto-lock topics that are some number of days old. On the Mac OS X board and the software board we really don't need to have threads that are over a week-old be bumped up to the top. It's usually bumped by accident, someone looking through threads that are a result of a search or someone who doesn't have much experience with webboards thinks people are still discussing something from october and responds "Yeah, that's right, I really hate that too!", and then a lot of people re-read the first 45 posts thinking it seems pretty familiar.
If someone actually INTENDS to dredge up ancient threads, they can just put a link to it and say In <link> this thread</link> Jim said <quote>Something from a long time ago</quote>.
On some lower-traffic boards a longer time-limit would make sense, but still there should be something.
~BS