I have never been to the prophecy site and like you, probably never will but I think I remember reading about it on 2+2. They have been using pokertracker or something like it 24/7 on many computers to harvest the play data on as many tables at Party as they can keep open. They have amassed a huge database and are selling it. The last time I checked, it had no way of tracking name changes.
To do something like this would be resource and time intensive.
If a player only plays a certain level (10/20 or 15/30 etc.) then he/she can basically do the same thing, but on a much smaller sample size. Of course when playing, even if you aren’t playing 4 tables, keep 4 open and when you aren’t playing keep 4 open and the software will continuously track. Doing this 24/7 for a couple weeks within a certain limit will amass a large database of players you are likely to be playing against.
I offer the pokertracker software through a link on my site and have a review of it that reccomends it. I have no plans to go any further than that. I will say that anyone who plays poker online for more than fun should absolutely try it, if only to analize your own game. It is a great tool. They have a free 30 day trial download (no CC or anything else required.)