We've seen plenty of geek t-shirts grace the virtual pages of Tech Digest before, but I don't think none of them match the geek cred exuded by this web 2.0 effort. No, not even the flashing Wi-Fi reception top. As your beady eyeballs can see, the shirt features a list of all the most popular social networking sites - all 79 of them. Wearers can use a marker pen to tick off all the sites they belong to, then...