These sites are confirmed in-game:
http://www.landau-luckman-lake.com/ - The official site for Landau, Luckman, and Lake, the law firm who represents Jake Starkey
www.cfrg.us - the Centre for Responsible Government; a conspiracy theory site where Jake and Caretaker sometimes leave messages for us
http://www.Coyotedispatch.com - The Coyote Dispatch, a local, weekly Catalina newspaper
http://www.nru.us - New River University, where the research on the time travel device is being done
http://www.geocities.com/meghanstarkey/ - Meg Starkey's weblog; she is Jake Starkey's wife
http://hexeditor.blogspot.com/ - Reggie's weblog; he designed the computer systems for NRU. He's also schizophrenic, so his writing is a little stream-of-consciousness