From the thread:
With this script you can easily store and retrieve all your materials, objects, textures, etc. You can also quickly share your stuff with other Blender users by using the built in import/export functionality.
Since this is a beta script, there are a few issues still to be resolved (a full python installation is required to use the import export functionality, the .blend file needs to be reopened after adding something, favorites aren't working, etc.), but it is still a powerful tool. Blender Library is certainly a great addition to anyone's Blender arsenal.