You mean delete other people posts in your thread like on facebook comments?
probably corruption on a discussion thread! (delete the ones against you)
Or like deleting a thread you made?
On changing the title, it only works if your the mod of the forum. Then you double click, but in IE8, it doesn't work for me ;_;
it goes to the edit thing then directs me to the page... :/
But it would make sense if there was a time limit, since editing posts really soon after you reply doesn't show the edited at so-and-so time message.