Slidematch is a media rating, contextual retrieval, peer recommendation, and library management system for music, video, movie, and book impressions. It adds value to your existing media player by enabling you to easily record detailed impressions, retrieve content appropriate to what you are currently doing, and interact with friends.
TOCC is a Tool for Obsessive Compulsive Classifiers. It implements a file system that uses tags instead of folders, allowing you to classify files however you want. For example, you could tag photos by location, people, and technique (e.g. black & white, HDR). Finding files is as simple as running a query like "give me all files tagged photo and my-love".