This is old code, just moved here. [We do not log for which user an error happened](https://github.com/peerlibrary/peerlibrary/blob/master/server/errors.coffee#L25). So we still log the error, but in a way that it is (hopefully) anonymous.

My idea is that for both error logging and reading state logging we would have later on preferences in the account settings with three options:
* respect DNT flag (default)
* allow
* deny

So the idea is that by default we use DNT to determine if user wants to be anonymous or not (for errors this means we do not assign user to the error, for state tracking this means we do not track them at all). But they can also explicitly opt-in or opt-out (they can decide that they trust us more than ad networks, for which they use DNT flag; or they decide that they do not want at all, despite DNT not being set).