More and more web pages are showing up with links to Facebook (facebook.net) and Twitter (twitter.com) and with that I find that page loading hangs up when connecting to these links; I have blocked both Facebook and Twitter from setting cookies in my browser (Firefox 8.0). The problem could be coincidental — but I doubt it, since the problem occurs whenever those connection attempts show up in Firefox's activity bar.

Is there any way of preventing Facebook and Twitter from "befouling" my browsing?