It is practically impossible to be an anonymous scientist. Prior to the internet era, scientists were known only for their printed and peer-reviewed publications, books and reports. Today, with or without our permission, every single thing you do is linked, tagged, connected and associated with some indexing service. The initiatives such as http://www.researchgate.net and http://www.academia.edu are making our life simpler in some sense, but at the same time very difficult: you need to be really determined to avoid it.