WHY HAS MARK ZUCKERBERG SET UP A FACEBOOK PAGE FOR HIS DOG? Not content with starting the whole social networking trend, Mark Zuckerberg has now created a Facebook page for his dog.And he's not the only one Jesse Eisenberg's portrayal of Mark Zuckerberg in the Oscar-winning film The Social Network was memorable – and deeply unflattering. Now the Facebook founder is rebranding in a subtle but effective fashion. He has got himself the best possible tool to engender goodwill: Beast, a fluffy little dog. Even better, he's set up a Facebook page for his new addition. Sample update: "I just took a dump and made Mark Zuckerberg pick it up. It was glorious." Beast is listed as a "public figure" on his page, and a short biography informs us of his pedigree: he is a puli – a breed of Hungarian sheepdog – and was born in Oregon before relocating to join Zuckerberg and his girlfriend Priscilla Chan in Palo Alto, California. He lists his interests as "cuddling, loving and eating", and displays a slightly immodest streak by declaring: "I am extremely cute". We'll be the judge of that, Beast. The accompanying photographs give us tantalising glimpses into the home of one of the richest men on the planet – shiny wooden floors, trendy exposed beams, what looks like black-and-white photography on his walls – and Beast is no slouch either: he eats and drinks from matching (real?) silver bowls. Pets on social networking sites are huge – high-profile Beast is liked by more than 42,000 people so far – and more and more of us are creating online lives for our companion animals, despite Facebook rules that state you must be over 13 to use the site (at just two months, even in dog years, Beast is only 16 months old) and, more importantly, you cannot create a profile for anyone other than yourself. But who befriends a dog on Facebook or follows a cat on Twitter? And why? Many of us consider our pets to be part of the family, and our families are all over social networking, so making a Facebook page for them assumes it is what they would do if they had opposable thumbs. Yasmin Eshref set up a page for her cat Georgie Coalie, as a joke to cheer up a friend. "But then lots of friends started adding her and sending messages to her," says Eshref. Georgie passed away last year, but lives on on Facebook. "I suppose I kept it up for sentimental reasons, like not wanting to throw away the possessions of a dead person. I know it sounds a bit naff, but it's just hard to let go," she says. One friend tells me she has befriended a dog belonging to a friend on Facebook. "He even posts updates. I love him." But another follows a puppy she is less than enamoured with: "Truly, I think it is slightly ridiculous. I did it to avoid offending my friends. The dog is cute, but I'm not that into him." Animals on social networking sites have enormous numbers of fans. Sockamillion, a grey-andwhite cat belonging to computer administrator and historian Jason Scott, tweets under the alias Sockington and has more than 1.4 million followers on Twitter. His list of followers reveals hundreds of tweeting cats and dogs. There are also spoof accounts for Bo, the family dog of the Obamas, and, of course, Larry, the newly acquired Downing Street cat. Fictional animals are doing just as well. Scooby Doo, Gromit and even Aleksandr Orlov, the meerkat from the car insurance advertisements, have Facebook pages. Full disclosure: I myself am friends with Fred, a plastic hippo who travels the world. Why do we do it? Because it's harmless, silly fun. It's the equivalent of dancing drunkenly with your dog at Christmas while he sends you murderous glances: we do it because we can.