How do you go about blocking Facebook.com with out breaking all sorts of other pages because of the ads? For example, if I blacklist facebook.com, when surfing the web (with IE8)on some sites (arstechnica.com for an example site) you'll see two or three OpenDns pages when you click on the down arrow next to the browsers back button. This has been keeping users from navigated to the previous page they were on with just a single click of the back button. I've had a chance to experiment a little bit with just blocking login.facebook.com and others but I figured someone has already figured this out and I should just ask...

Thanks!

Many domains load Facebook's sharing tools and options; domains may load incorrectly if you don't allow the request to Facebook to go through and generally there is no way around this is if you want to really block Facebook.

The more commonly blocked domains that may result in errors when Facebook functionality is present are:
facebook.com (of course)
fbcdn.net (Facebook's CDN)

You can try blocking sections or subdomains of the Facebook domains listed above, which may improve the issue you're seeing.

Don't forget to flush your web browser caches and DNS resolver caches after changing your settings.

Browser Cache Flush: http://www.opendns.com/support/article/327
DNS Resolver Flush: http://www.opendns.com/support/article/209