Social Media Sites for the Library

The fantastic options that today's social media sites allow libraries to explore is overwhelming (in a good way)! To give a quick and dirty summary of how I would employ YouTube, Flickr and Pinterest in a public library setting, I'm just going to make a few lists:

YouTube:
-Tutorial videos of how to use different library resources (catalog, downloading e-books, how to print in color or b&w)
-Videos of the inside of the library to show patrons where to find certain collections or to introduce possible patrons to what the library looks like
-Posting YouTube videos of [books made into] movie(s) trailers and book trailers to the library's website or Facebook page. Any YouTube video that is relevant to the library in some way could be posted!
-Videos of librarians & staff who work at the library--introducing themselves, explaining what they do at the library, hopefully creating a friendlier web environment for patrons


Flickr:
-Sharing photos of the library's new collections (all different fiction genres, non-fiction, YA, children's, DVD's, etc.)
-Photos of the library and its signage to familiarize patrons with how to navigate the stacks
-Good for non-fiction collections to showcase photography materials located in their collections

Pinterest:
-Similar to Flickr photosharing, but a more interactive interface, which will encourage more comments and "likes" from patrons
-Because photos pinned to Pinterest are directly connected to their original source pages, patrons can see a picture of a book that they want to borrow, and can click on the picture and be immediately brought to the catalog listing for that item
-Librarians can use Pinterest for their own personal use--perhaps creating pinboards of books they would like to buy replacement copies of, or a pinboard of ideas for programs or displays they can bring to the library

Does anyone else have any ideas of other ways these sites could benefit a library?