Firefox has a biultin spellchecker and underlines any misspellings in red - like it did 'biultin'.  I proof read and tend to notice red underlines.  The typos were added by someone else.  Many forums/blogs allow for changes by an admin and don't show as edited.

I would have to defer this to KD or hop, but for my time on this forum the only edits have been for spam, objectionable material or for sysops assistance to format embeded video or audio. If you make a typo or other grammatical error, you usually get beat up by other members. (ECA excluded) 

[Edit by RDH - I know, don't feed the troll.]

iM A HIT MAN..
I try to catch what others havent, and MOSTLY SPAM, or REALLY offensive(mostly the XXXX)..
If I catch it first, ITS GONE.
If I catch it last..It SHOULD have been gone.
Im VERY open minded..But that one with the FAT person POUNDING a poor guy, and the wobbling Rump, was abit much.  I dont care if he was 16", THE POOR GUY WAS GOING TO SUFFICATE..

Note that all edits are displayed in the bottom right corner of the post, sysop or not.  There is no way to remove the "last edited by" tag that appears there.  So if someone edits your post, you know immediately who did.