Newsweek has an article about social networking sites for pet owners. Some of the sites like Dogster have been around since 2004. Dogster now has 180,000 members from 125 different countries. Here is a list of pet social networking sites and their membership size as reporting by Newsweek
The sites let people created profiles for their pets that include photographs, hobbies, tricks, etc. They also have friend features like the social networks for people do. Newsweek's article left out a few pet-related social networks like Fuzzster, Backwash Pets and PawSpot.
Newsweek has an 
