This is an ongoing project to collect all of the info about how anonymous browsing with Tor can be subverted. The NSA has a dedicated task force for analyzing Tor and looking for weaknesses. There's obvious ones, such as disabling Javascript, and ones that aren't as obvious, such as changing your language and punctuation so as to avoid a statistical correlation attack. I will devote my each of my project logs to covering one of the vulnerabilities to your anonymity on Tor.
This is a problem faced by everyone worldwide, whether you live under a totalitarian dictatorship, or you just don't want everything you do online monitored and scrutinized by Big Brother.