How often can one bump a thread?
Is posting a reply to someone who replied to your thread considered a bump?
How many active threads can one have?
How does one go about closing or locking an old thread?
Any info would be greatly appreciated, especially from mods.
The only area with a strict bumping/posting policy is the Trading Post, and all such answers can be found in the rules and sticky posts in that forum.
Posting a meaningful reply to a legitimate question is not considered a bump, but those sorts of things can easily get out of hand and be abused, so it's best to take discussions to PM.
Members can't close or lock threads themselves, only mods can do so. We pretty much take care of locking or deleting threads as needed. Typically we only entertain requests to lock or delete a thread in special circumstances, particularly once others have posted -- the thread no longer really "belongs" to you at that point, and unless the thread is heading in a really bad direction (which would prompt us to take action anyway, without a request), we won't interfere with it. We've had people start a thread with something stupid, they catch a bit of heat for it, and then ask to have it deleted. Not gonna happen unless the flaming gets out of hand, so be sure of what you're posting and grow some thick skin to go along with it. ;)