Foursquare, Yelp and Gowalla are becoming the universal guide books

Gowalla, Yelp and Foursqure allow people to define venues on their smartphones. This is creating a rapid crowd sourced guide to the entire world which is going to do to the guide book what Wikipedia did to the encyclopaedia.

Problem still is roaming charges and poor access in many nations. Until the carriers are forced to make more reasonable prices to global travel users the true potential of this new way of finding and defining places to see will be extremely limited.