When AOL introduced 5 GB of online storage--for free--there was much rejoicing. The service is called XDrive. But that wasn't the extent of it. For a reasonable premium (that's ten bucks a month), you could get 50 GB of online storage. Not a bad way to keep a few backups handy. AOL also jumped in the sack with JSON ("jay-son"), a web API that allows developers to work the XDrive into their own apps.

One such app is the Open XDrive Usage Meter Widget for the Mac's built-in widget system, Dashboard. The widget includes analog and digital readouts of available storage (in megabytes) and offers configurable thresholds for low space warnings. The background of the widget will change to yellow and then red as you surpass those thresholds. And, as the author of the widget points out--it's already compatible with Leopard, the next release of Mac OS X.