Snark is for users of Facebook. Sometimes it's hard to express yourself, and many have clamored for a FB "dislike" button. Using Snark you can type whatever you want and then choose the icon that fits your mood. You can save your creation to your computer as a jpeg image. Now you can upload it to your wall or to a friend's or group's wall. It's formatted to look just like a Facebook comment.
How does this work? The program converts a Flash movie clip to a jpeg, using some custom classes and a little PHP. Drop me a line at facebook/sonam.miller if you want to look at the source code.