I heard someone say the other day, that some universities and businesses were blocking face-book from their networks, because, it chewed up too much bandwidth because it was pulling data from so many different sites.

correct me if I'm wrong, but face-book, is for the most part fairly light on AJAX (I mean google apps and what not use a lot more AJAX than facebook), and really heavy on PHP, which means that all of the bandwidth pull and processing is happening server side.

It might take a long time to load, because their servers have a lot to process, but it doesn't chew up much more bandwidth than any other site that you visit a lot...