As a regular twitter user the one thing that bugs me most is when I spot something I have tweeted (invariably after it has already been favourited / retweeted / replied to and I don’t want to delete it) and I spot a typo / spelling error. If this happens on facebook I can simply edit it but my inability to do the on twitter is frustrating. The suggestion is simply to have an ‘edit tweet’ option. Abuse of this (eg. completely changing tweet) could be limited by limiting number of characters changed / added / removed and/or by showing underneath the tweet a comment saying ‘edited’ and an option to click ‘view original’.