If you check the bottom of each thread, we find a list of similar threads to the one thread we're currently viewing. It's actually very useful, but sometimes not. Why not? only because it includes threads from way back when. I'd like to suggest a time cap on the threads shown in that area, like perhaps only show threads made within 12 months from the day you're viewing it. or 6 months prior. Coz threads that are really really old (although good for informational purposes for a history project or whatever) are really out-dated, and useless - especially ones made in the marketplace. We're interested on finding similar threads but not outdated ones that we can't use anymore. It would be perfect otherwise, if it didn't include old old old dead threads. Don'tcha think?
The 5 similar threads are stored on a per thread basis when the thread is created (it does not search for them dynamically when you are looking at the thread). It would be a pretty big load on the DB servers to try and do that every page view. Because of that, there's not really a way to put a date consideration into the query based on the current date.
What is really pisses me off when some Bozo takes one of suggested threads made 5 years ago and then made post in there replying to OP... arrrrrr fastreplies