I've been around here since early 2005 and I've never needed to edit posts for more than a couple hours. Sure, I read some old material I posted long ago and see typos, poor grammar, fuzzy writing and would like to 'update' that old text, but it's not a pressing issue for me.
But what if my ideas on skiing tend to change with time? Should I go back and change what I wrote five years ago because I no longer see things that way? What does that do to the original multiple-way conversation?
I don't know about others here but I tend to proof-read what I write before I hit Submit. Even so, sometimes the spell checker fails to underline mucked up words or I miss otherwise nonsensical collections of words (read: Space-outs). Here it's nice to have a while to proof-read the actual post in its new sequentially-relevant home and make corrections/modifications based on other posts that may have jumped in while I was writing.
But after those corrections, modifications and restylings I've no legitimate reason to change the text in that particular post. That final proof-reading is perfectly sufficient for me. I can always amend my statements in a later post if I subsequently think differently - but that's the key here: subsequently
! If a post later than mine changes my perspective, my thinking or my position on a subject then is it really legitimate for me to go back and change the writing that reflected my earlier thinking? An endless edit feature might be used to criticize and insult other people, then hide it later to make it seem like the other fellow is making things up when he retaliates. ("Did not!", "Did too!", "Oh yeah? Prove it!" - but now the text is gone...)
I'm greatly in favor of a one or two hour time limit on post edits! If I really need a change to an old post I can simply re-write the offending post and submit it to a Mod (or Admin) and request a replacement. This also prevents anyone from "changing history" inappropriately because the Mod will likely evaluate what changed and call me on any mischief.
Just because an electronic medium lets us change what we said earlier doesn't mean we should enable that feature when it's inappropriate - and I think a shared discussion forum is just the place for keeping accurate footprints in the sand. Copyright may affect how material is used but putting material up here is effectively placing it in the public domain.
A further idea is that your own writing is contributed to a larger tapestry, intertwined with that of others. Changing your writing long after a thread develops effectively changes that tapestry thus affecting the writing of everyone else. If the entire "Thread" is taken as a 'work of writing' and EpicSki (or any forum provider) is the copyright holder of that Thread (in it's entirety) then I've got to wonder if changing past components of that 'overall work' infringes on the forum provider's Thread Copyright...