While Identi.ca is not nearly as popular as Twitter, this open source microblogging service is home to many open source advocates, developers, users, and just interesting people. Thanks to a Twitter-compatible API, many closed source Twitter clients for the Android platform will happily work with Identi.ca. But why settle for a closed source app if you can install the excellent open source Mustard client?

Mustard is not the most advanced microblogging app out there, but it offers all the essential features and a few clever tricks to boot. It supports multiple accounts and sports the geolocation feature which attaches current geographical coordinates to your posts (you can, of course, disable this feature, or specify the desired accuracy). Moreover, Mustard allows you to attach files to your status messages -- handy if you want to post photos on Identi.ca. Using the context menu, you can subscribe to a user, re-dent the post you like, mark it as a favorite, and reply to the author. In addition to that, Mustard sports powerful searching capabilities which let you search for users, groups, tags, or posts. Mustard is available at the Android Market, or you can grab the latest version of the app from the project's Web site.