I have been using Facebook since early 2008, have read several people's articles about it and logged them, with view to MCLIP revalidation, and have, for 23things, added the COPAC widget to my Facebook page. I made a guarded attempt to use Facebook as a blog in the autumn of 2009, but I have never had the same enthusiasm for it that I have for some other Web 2 applications.
Reasons include the site's terminology that makes 'friends', or not, of people whose relationship could be better described in other ways, the invitations to games offering minimal interest in return for account details, the sense that Facebook brings together play versions of lots of things that thrive better in a full-size version elsewhere. Facebook does photos, but without Flickr's ready searchability from outside and innovative approach to rights. Facebook notes are like a blog, but with a smaller typeface than Blogger. So far as I can see, anyway. I have done what I can to confirm this general perception by uploading a few photos; you will obviously be in your rights to correct me if you know better.
I don't hate Facebook with the level of aversion that Miss Crail reserved for Twitter. But, in pursuit of 23things, I find that Facebook is for me neither a new thing to explore, nor a hobby that I'm eager to expound.
Hence I am not drawn to getting up a library Facebook page in addition to the library blog. Ready though I am to see that others have made a go of it....