This might just be for forum games, but a lot of times there a people with only one post who revive dead threads. How do they find threads several pages old and believe they are active games?
They either accidentally do it (because sometimes old threads show up in the realm of new threads and they post without looking at the date), or they intentionally do it (by selecting a thread that is far into the forum record).
What is wrong with reviving old threads? Isn't it better to take up a thread that already covers a subject you have comments on than to start a new one? I never understood why people prefer spamming up forums with lots of similar threads instead of using one that collects all comments, no matter how old it is.
Personally I reply to any thread I please, I never look at the date, and when people complain about me doing it, I just ignore them.
This is where the common misconception comes in..nothing is wrong with reviving old threads. I've done it PLENTY of times. The problem is reviving old threads by either posting a spam post or not adding anything to the discussion.
If you revive and old thread but do so in a way that actually adds to it, it won't get necro'd. Everyone always thinks there is some time limit, but there really isn't. It's just spamming an old thread or reviving solely for the sake of reviving.
They can also find them through Google as well. Ressurecting an old thread just to be funny is considered "Necro" and the thread will be closed. Posting something valuable to an old thread is just fine.