According to my big brother, quoting 'Dunbar', I assume this is a person's name and not the town near Edinburgh or a life insurance company, it's not possible to have more than 150 friends. I mean it is, to have 'friends' (see the blog of unnecessary quotation marks below) on facebook and the like. But there's a critical number beyond which they're not really friends but just people you vacuously toss a few platitudes towards, or, like someone said, give the Duke of Edinburgh handshake (the one where it's both saying hello and goodbye at the same time)..so all those people with 300..400..500 friends on facebook are just deluding themselves.
Still, that leaves me with room for about another 147 anyway!!
Seth's Blog-the original internet marketing guru (he'd put it in a much less hackneyed way than that)