If you ever need to show a patron or coworker (or family member or friend) how to use Facebook or Twitter, be sure to have these Mashable guidebooks handy! Each guidebook goes into nice detail (in a nice, accessible FAQ style) on a variety of topics from the basic (setting up an account) to more advanced features (sharing music or video, hiding Facebook notifications). Why reinvent the wheel with great tools like these around? Oh, and while you're at it, subscribe to Mashable's RSS feed - you'll find tons of great info to be discovered.
Thanks to Stephen's Lighthouse for the lead.