Given the importance of relationships within Facebook, folks would like it to offer a more appropriately expressive set of, er, ‘relationship assertions’ (you get to pick from a list of tick-boxes). An interesting confluence of opinion: Dave Winer, John Naughton, Stu Weibel, Jon Udell.
The library does not have a singular network presence. There may be a main website, but the library also syndicates its presence to other venues (e.g. RSS), has unbundled to social sites (e.g. Facebook), and sources activity in the cloud (e.g. LibGuides).