Some of them actually keep detailed records. If you regularly do well at a given tournament that is an indication that you should be studied.
So, a player may start examining your play in a tournament. They will record betting patterns, style of play, how often you get on to a final table, etc.
So, yes, some people may use info the gain from sites the lists players statistics.
But, not all of the people who know about your play do.
odds are if you are good enough to make money on a consistent basis, you are being watched. Learn to be a watcher so you can gain incite on your opposition because it is likely that they are doing it already.