The hydrus network client is an application written for Anon and other internet-fluent media nerds who have large image/swf/webm collections. It browses with tags instead of folders, a little like a *booru on your desktop. Tags and files can be anonymously shared through custom servers that any user may run. Everything is free, and the source code is included with the release. It is developed for Windows, but fairly functional builds for Linux and OS X are released at the same time.
I am continually working on the software and try to put out a new release every Wednesday by 8pm Eastern.
This github repository is currently a weekly sync with my home dev environment, where I work on hydrus by myself. Feel free to fork, but please don't make pull requests at this time. I am also not active on Github, so if you have feedback of any sort, please email me, post on my 8chan board, or message me on tumblr or twitter.
The client can do quite a lot! Please check out the help inside the release or here, which includes a comprehensive getting started guide.
I use a number of the Silk Icons by Mark James at famfamfam.com.