You now have the option to remove the "post edited by...." bit at the bottom of your post should you bugger up your spelling or something like that.
Its always annoyed me, dont know why I didnt can it earlier.
If you change something substantial its a good idea to leave it in, along with a description of what was changed so others can be up to date.
Note posts cannot be edited after a certain time.
More on this in v2.0