I have no idea what point he is trying to prove, but I did t get any birthday wishes from all sorts of services this year. I don't know how people use Twitter, but it's reasonable that it is used for non-personal relations, such as keeping up with celebrities and bloggers and such. Why would they wish you happy birthday?
(Assuming this isn't sarcasm)<p>I'm not sure you can extrapolate from one person to hundreds of millions. Also, how much does the writer use twitter? If you never communicate with others on twitter, they'll never communicate with you.