A silly workaround to 'blocking' is to create a local host entry for gator.com, and anything else you want, and then you'll never go anywhere for those domains. Thus not having to worry about blocking it, because gator will use, or even redirect if possible (including IM and P2P) out on port 80, so it's kind of difficult. If your machine is XP, you'll want to watch what names are being resolved by reviewing your dns cache, using ipconfig /displaydns, and then put in each entry that you don't care to have actually resolved. If you had a local DNS server, you could simply create zones for each domain and that would do the same thing.
OK, so stupidly long post, but you get the idea, which is the path of least resistance IMO.