Forum Moderators: open
Things can change, and if they do, there should be a new thread on the topic instead of continuing to add onto the older one. If it's the case that you need to talk about that specific thread that is now locked because it is outdated, then you should start a new thread and link back to the old one, anyway.
For example in the bot tracking forum, if there is only one thread on a bot, and it's only got a few posts, but it closes after a month, you end up with a fractured conversation (or none at all if the person can't bother to start a new thread).
It also ruins the pages for seo - ie. the keywords won't appear all on one page.
For example new members could not bump threads older than 120 days but senior members can add to threads up to 180 days.
Another factor could be short threads. If a thread only has a few posts (single page) it could be added to up to 180 days, to keep the subject all in one place.
Like I said, it's kinda silly to have a topic with just two posts about a bot and there is no other thread on it, and there's something to contribute.
If someone has subscribed to an older thread looking for replies on the subject, and you force people to start new threads, the person subscribing will never hear about it.
case-in-point: there are more threads rejected in the premoderated forums by older members than by new members. Go figure...
Now, that is not to say I don't agree with what you are proposing in some forums. The code forum threads tend to have a longer life span than a topical news thread in one of the search engine forums. However, those threads in the code forums, often mention a site or url and get mysteriously bumped by someone.
Far worse. :) Proof positive: this "very old member" just bumped this thread after almost a full month, right?
>>The code forum threads tend to have a longer life span than a topical news thread in one of the search engine forums.
And rightly so, some of them are pure gold (though not all). Some threads in the code forums need to be in the forum Libraries as "Golden Oldies" because they're of timeless value.
>>However, those threads in the code forums, often mention a site or url and get mysteriously bumped by someone.
Too true, and they get found, too. Just recently I've sent a note to some forum mods about a thread or two with bad or questionable or dead URLs posted, and then realized that the thread was old, from several years back. I actually felt kinda silly (and almost embarrassed) when I realized when the threads were from - but that's what can happen when you figure out how to drill down into searching on the site for specifics and find older threads.
Personally, I can think of a thread or two in the PHP Forum Library that would hugely benefit members if they were opened up again (and maybe should be), for those who need certain points clarified. In those cases, I think maybe sending a sticky to the mod and/or starting a new thread with links to the Library thread (and a sticky to the mods) would be the answer.
Case in point: Library thread about a 5 minute or so PHP template - pure platinum.
There has to be some logic that can be followed programatically to keep shorter threads open longer just in case there's a good follow up later. ie. membership age of topic starter, last poster, type of forum, etc.
Wouldn't stickied "Hot Topics" threads like tedster does in the Google forum work well to serve members on "pet issues" that seem to recur year after year?
Know what I currently see as a problem area? There are Wordpress threads scattered around all over the place in different forums here, with no way any newbie could ever find them, even though "Golden Oldie" members can find anything at all on any topic here at WebmasterWorld.