I once did a search for the oldest post on this forum. I dredged the following up from April 2004. The OP posted once again a year later, so technically it was only dead for 6 years. Anyway, he's the first baby!
Some forums I frequent will lock a thread automatically after no post in 6 or 8 months. The weird part is that a question can be asked, answered, then forgotten and locked, then somebody the next year will ask the same question with a twist. Only the forum community will cry foul that the question has been asked before and to run a search. Guess it serves it's purpose.