Name: Vitalik Buterin
Somehow we need to persuade these members to become active in the forum again.
I really dislike how a few successful altcoins only used Bitcointalk to gain publicity, and abandoned the forum the moment their premined bag of altcoins made then very, very rich.
When the topic starter is gone for more than a year, I'd say it's time to lock the thread.
Something came into my mind reading your post...
I know that auto lock is evil, but:
what about auto locking the topic if the OP don't visit the forum for e.g. 6 months? (3 months, 1 month, etc...)
If OP don't show up, that means that the topic has served it's purpose, so it's lockable.
I know that there are some megathreads with a lot of information in it, but the information won't vanish if the topic is locked. Everyone can open a similar topic, if needed to continue the discussion.
Or, OP's should 'keep alive' their topics, they should click on a button (only visible for the OP) periodically, not to let it auto locked after a month or so.
This would solve the problem of the OPs who open a meaningless topic just to increase the post count and let the topic become a spam megathread, because other spammers are happy to post in a meaningless topic, especially in the off-topic section. I know that this is not the perfect solution, but could limit spammers a bit.