GTA IV went far above and beyond, as Rockstar usually does. If you happen to pass by an internet cafe in the game, hop on a computer and try some of these websites in the game:
If you whois them all you’ll see that they have “private registrations”. But all of these domains are taken (In Real Life). A quick search on ebay reveals 78 .info domain names of almost all of these going for $6000.
References:
http://faqs.ign.com/articles/871/871172p1.html
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=160236465134
Grand Theft Auto 4 blogging 