Facebook is the worst script ever written for the Internet. The sole purpose of Facebook is to dominate the web and sell your information and they're doing a good job of both. I fully agree that most forum posts are useless after a given period and 90% of the garbage stored on the Facebook servers is equally useless.
Your suggestion that forum posts only linger for a certain time has a lot of merit, but I still think the time already allocated to fix typos is probably enough. Maybe it could be doubled, but please let's not fall into the Facebook way of thinking.
Cheethah already clears personal messages after a specific time if I recall. I think it's 30 days, but there may be an option somewhere for admins to change it.
The current forum is basically an add-on to the original Dolphin and it's not brilliant. Deano plans to revamp it and it should be possible for the options you suggest to be added when it happens.
If you add you wish list to the Suggestions page, Deano can access it when he's ready to start work.
Thanks for the comments. I have given this a lot of thought as I looked over how other platforms deal with this issue. I believe that people both make mistakes when they post, and they change and grow. So having a permanent unchangeable record is great for a news source, but not so good for a friends community. When people can reword, rethink, revise, fix typos, or delete bad ideas, they are more willing to engage. Some sites may want to be a clear record, but others may want to be more like a friendly conversation where people have the "right to forget". Texting has the immediacy of spoken conversation, with the permanence of the written word. Thus, often texting has knee-jerk reactions that never ever just go away like they would in a spoken conversation.
To deal with the issue that Johnk brought up, with comments perhaps not matching an edited original post, I suggest having Cheetah send a note of a change to anyone that commented. Then they would have the opportunity to adjust their comment or delete it.
Also, perhaps a site specifically doesn't want to be a permanent record. Could we have a setting to delete everything posted after a certain amount of time? Perhaps someone could mark if they want it to stay, or how long it will stay?
Most social network conversations are pointless after a week or so. Telling a friend Happy Birthday doesn't need to be stored for permanent record. Their are many reasons for a site to choose to let the back and forth just vanish. Let's face it, I didn't need Facebook reminding me that I used their platform to let my family and friends know that my father died. I didn't use that platform when my mother died, because I didn't want that popping up in some "memory". I got the information out, I know when and what, now let me forget it.