Truth,there is no such a thing as "privacy", It is not safe to keep any sensitive data on a PC which has internet connection:/ It is easy to dig any info about any person who has accounts in the internet and e-mail is the best way to start. The most of people think that newer web browser ensure their safety or newer firewall or anti-virus and they are absolutely wrong. Sensitive Info must be kept crypted in PC (personally I think TrueCrypt is a good choise), http isn't safe, only https, but the most of web-pages use only http protocol.
here is a list of web-sites and programs which helps to surf safer by hiding or encrypting your internet path:
http://ipinfo.info/html/anonymous-surfing_2.php
it can't ensure full safety, but it helps a lot:)
It is a big risk to have accounts on web-pages like myspace or facebook and etc..