I'm a member of other forums (admittedly quite dull) and on those forums the author of a post can exit a post, or the OP can delete the thread they started.
Ive noticed I can't do that on here. It means if I write something and then want to change a typo or add something I have to put it as another comment - it gets quite tedious to read threads where a lot of it is people correcting themselves (or getting abuse for not correcting a typo)