Here's just some examples of threads that I think could benefit from the option to edit after 24 hours:
Mod's editing
Liz updates this post so often when WarPath could be perfectly capable to do it himself...
APPLICATION FOR CA CODERS
First post Could be updated with information about who is on the Hackteam
Everything in this forum
MPGH's public hack is outdated, but people are still posting, thinking it works.
In this case the title could be edited
I know I have many posts that are misleading because halfway through the conversation we realize that the original thesis was wrong. This is one of them
Change title
This one has been irritating me for weeks now. I have known for a while now that you can't edit .rez files with a text editor, but I can not edit the title so it is misleading to people just joining the thread.
Keeping Lists Up to date
This is a thread that I want to keep up to date, but I can't because I can't edit posts after 24 hours.
Infinite Polls
These things take forever to fall to the bottom of the forum because people keep voting. With editing the maker of the posts could close the thread.
The Ability to edit posts after 24 hrs has a lot of benefits:
1. Collects all the information in a thread to one spot (in the case of the first post)
2. Allow people to update their posts or make corrections
3. If No one else posts on a thread in 24 hrs and some1 wants to make a correction they can make it without creating a whole new post.
4. Stopping polls
etc.