It appears the obvious answer may be correct:<p><i>The reason that certain tweet content appears to do nothing is that Twitter is interpreting them as commands, according to this article:</i><p><a href="https://support.twitter.com/articles/14020" rel="nofollow">https://support.twitter.com/articles/14020</a><p><i>The get command will send the latest tweet from the named user to your phone. I've tried some of the other commands listed in that article, and they don't post a tweet. They do, however, have the listed effect. For example, fav accountname does indeed mark the most recent tweet from accountname as a favourite.</i><p><i>It's perhaps useful to remember that'd accountname Some message here will send a direct message to accountname, even if entered in the public tweet box or via another client. This shows that they have a standard text to action parser that works on tweets as they are submitted.</i><p><i>So, to answer your question: No, it's not down to Jack Dorsey's father. It's purely because Twitter is interpreting it as a command. Sorry!</i>