I think that it is legitimate traffic, but there is a ridiculous amount of it: ~250 requests per second. I made several changes to speed up the forum, which seems to have helped.

Some changes you may notice:
- The users online list at the bottom of the board index is gone. That was too expensive.
- Searching is now subject to the same spam protection limits as posting. So newbies have to wait 6 minutes between searches and users with more posts have to wait progressively less time.
- If you request pages faster than once per second too many times, your IP will be temporarily banned.

I wrote my own caching system because I didn't want to use memcached, etc. There may be bugs with this. In the future I may need to add more aggressive caching.