you tube is so popular because 1. we like to show other people the crazy stuff we do and 2 because we like watching the crazy things other people do. YouTube can be addictive- there are so many videos that you can find something about almost anything (I found instructional videos on origami) and because of the clever way new videos present themselves to you once you have finished watching the first... you just have to check out one more, then oh! that one looks interesting too, I'll just have a peek ... and so on until its 2am and you can barely keep your head upright.
The video I posted is a diver's video of a Mola Mola - a really big and strange looking fish. I've been a teensy bit obsessed with them for ages- they're just so strange- and then I saw one off the island in the picture I posted below. That was a great day.
Sooo, the library could embed videos into webpages with instructions of how to use the catalogue, record storytime and post it for playback later(I'm totally kidding), create virtual tours around the library so people know which floor fiction is on, create promotional videos that show how great the library is (wait, we already did that), or put a speaker's corner of customer comments on the webpage, obviously screened beforehand for appropriateness ect.

Dover Island

S3600100, originally uploaded by lotustiger73.

this is a shot of sunset on Dover Island, an amazing little bit of rock in Peggy's cove area in Nova Scotia. I had the good fortune to spend a night on the island this past summer - oh the stars!

So, I suppose the library could use Flickr as a navigation tool, showing customers where things are and how to get to them... it could be used to post pictures from events, a BPL group could be created for customers and staff to share pictures of, say, Burlington or other themed things, we could do photo contests, savager hunts using obscure pictures of places in the city that people have to figure out and go find....
...that's all I've got right now.