It could be fun in a World Language Classroom to use Fake Tweet Builder. Your students can work in pairs and develop a dialog using words from their vocabulary list on a topic that goes along with their lesson. Avatars and backgrounds can be uploaded to go with the theme. An image file of the dialog can be shared on a blog or within Google Drive. They also have the choice of using the Submit button to post to Cheezburger.com. Here is a quick example I put together.