There have always been rumours that there were ways to see past the anon flag. As a long time user, I know that back in the day, the site was quite buggy and there was a lot of exploitable errors, but Admin were told about them and they were fixed.
If there are any ways to see past the Anon flag now, I don't know of them.
Some people here can still be reasonably anonymous. Others cannot be anonymous at all. For instance, I can post this as anonymous yet anyone can easily determine my actual username. I leave it as an exercise to the reader as to how trivially easy that is to do. No doubt someone equally as bright but more forthcoming than I will shortly tell you now it's done.