This is an excellent article concerning the authentication of web pages for evidentiary purposes written by M. Anderson Berry and David Kiernan. An excerpt--
Plaintiff sues your client, claiming that his injuries have significantly affected his lifestyle. He is unable to work, travel or bowl. Not surprisingly, his spouse alleges loss of consortium. On the eve of trial, you discover pictures and other details on a social networking website about plaintiff's recent trip to the International Bowling Museum & Hall of Fame, including a picture of plaintiff proudly holding a fluorescent orange bowling ball and a four-foot tall gilded trophy dated four days earlier. As you approach the witness with printouts of the web pages, you are stopped in your tracks: "Objection, lack of foundation."
The article contains tips for authenticating web pages pursuant to the Federal Rule of Evidence, easily adaptable for state court arguments. It also has an interesting section about court cases involving the Internet Archive, a digital archive of web pages that are no longer active.