An interesting article on NYT. Two things to take away: Internet does not forget anything that you post publicly, don't expect complete anonymity these days if your actions are questionable.
The collective intelligence of the Internet’s two billion users, and the digital fingerprints that so many users leave on Web sites, combine to make it more and more likely that every embarrassing video, every intimate photo, and every indelicate e-mail is attributed to its source, whether that source wants it to be or not. This intelligence makes the public sphere more public than ever before and sometimes forces personal lives into public view.
To some, this could conjure up comparisons to the agents of repressive governments in the Middle East who monitor online protests and exact retribution offline. But the positive effects can be numerous: criminality can be ferreted out, falsehoods can be disproved and individuals can become Internet icons.
This erosion of anonymity is a product of pervasive social media services, cheap cellphone cameras, free photo and video Web hosts, and perhaps most important of all, a change in people’s views about what ought to be public and what ought to be private. Experts say that Web sites like Facebook, which require real identities and encourage the sharing of photographs and videos, have hastened this change.