Twitter is more than just a communication tool. Did you know that you can even use it to remotely control another Mac or PC?
That's what TweetMyMac allows you to do. Not only that, but TweetMyMac allows you to take screenshots, iSight snapshots, and obtain your IP address from your Mac just by sending a direct message to a specially setup Mac controlling account. You can even start torrents remotely and shutdown your Mac.
To get started make sure that you setup an entirely different Twitter account otherwise, anyone who is following your regular account will be able to control your Mac using TweetMyMac! Once you've done this, set the account to follow your regular account. Once you've installed and signed into TweetMyMac using the details of the new account you've just setup, you simply send direct messages to the account to control it. You can do this as a direct message such as "shutdown", "restart" and even "screenshot". The full list of commands can be found on the developer website.
The only problem I had in setting up TweetMyMac was that once you've entered your username and password, there's no "OK" or confirmation button to click. It seems you have to close the program and restart it upon which it will prompt you as the accounts that can control your newly setup account. You can access the preferences again by clicking on the TweetMyMac icon symbol in the menu bar.
TweetMyMac is an interesting adaption of using Twitter on the Mac although it could seriously compromise your security if set up wrong and would only be useful if you have two Macs that you need to control at the same time.