2200001426
Recently I have been too paranoid to even use the same throwaway account because doxing has almost become an automated process. For example if you have a reddit account you can summarize your comment history with: http://www.snoopsnoo.com/.
Note I am not even considering the case of people with privileged information. The people who run HN certainly already know who I am since I didn't bother to clean up before switching accounts.
But I think it will be an inevitable certainty for you to be automatically deanonymized with just speech/thought patterns from comments alone. For example if you google for the phrase I just used, "inevitable certainty", they are only ~7000 search results. And now that I think about it, it is a really weird way to say it but it also a phrase I have used before.
If I'd kept using weird phrasings or kept making consistent grammatical errors like that, it will eventually be enough to build a fingerprint based on my vocabulary, understanding of grammatical rules, beliefs, timezone, etc. The more I talk the more information I am giving away for people or just machine learning algorithms to cross reference and link together my anonymous and real accounts. See this post for a real example (but limited to just the bitcoin subreddit instead of across the internet): https://www.reddit.com/r/Bitcoin/comments/3hf5z7/determining...
If you need to stay anonymous, don't interact with the world...