Perhaps there can be a compromise on this... maybe a 30 minute typo correction period should be used. 30 minutes should be adequate for practical purposes.
People should be given an adequate length of time to rephrase their comments and/or make typo corrections. But the use of unlimited time for editing or even deleting a message leaves the system open to the sort of abuse that has been occurring over the last several months. People's comments should be "locked in" so that there is historical accountability for everything that each one of us has said. To allow people to modify and delete at their whim and fancy, for fear of looking "stupid" as a result of subsequent posters' comments or criticisms, dilutes the value of the forum... I, for one, would not feel comfortable posting a well-thought out comment in response to someone, only to later see that previous member's post mysteriously disappear or appear in a modified manner (making me look like I am contradicting myself and, even more frustratingly, making my post and the time spent on it a TOTAL waste of my time).
We need historical accountability, but we also need adequate time to make typographical corrections. I believe that a 30 minute lock-out period for BOTH post editing and post deletions is an adequate compromise.