On many forums and websites (this one perhaps included, I'm not sure), when a user goes inactive for a period of time (six months, a year, whatever), their account is temporarily deactivated, and they simply have to verify through email if they wish to reactivate after a period of inactivity. I've noticed lots that people will manage to dig up topics that are anywhere from 8 months to 3 years old (where that was the age of the last post before theirs), and it will make it to the front page; nothing will be contributed to the topic except for"The download doesn't work" or"Can I use this [build/texture map/mod] in my YouTube video?" thus making this anecro-post.
My suggestion is simply to have an auto-lock feature that temporarily locks a thread when the last post was created six months ago; if the OP wishes to unlock their post, they simply have to open the topic and hit a button that says to unlock it, thus allowing it to be relevant again.
This idea would be wonderful in my opinion, as it would:
Spare members frustration who get unnecessary notifications about topics that were all but dead
Allow newer, more relevant topics to shine on the front page, instead of having tons of topics filled with old information, and then"Can I use this in my Let's Play?"
Save mods from having to manually lock posts because people decided to necro-post; this would get rid of it all together, for the most part.
This idea has been suggested a few times and while we certainly see the merit we've decided that we don't think that the cost is worth the gain. We don't mind people posting in very old topics, as long as the posts are constructive We'll always keep the idea in mind but for now we're not going to implement it.
Thank you for the well worded and explained suggestion, super helpful. Thanks!