You should read about how ratings work for the site. It is very likely that the player in question has a high Ratings Deviation ( RD) and has bigger jump in ratings than you do. The implication there is that your RD is lower and therefore your rating is more accurate.
http://support.chess.com/Knowledgebase/Article/View/16/0/how-do-ratings-work
I've just been passing my time in a 10min tournament for 1200 to 1500 players. The player who finished first started out rating 1498, ended up 1614.
How can this be possible? That's an average gain of 23 points per game played. Now I only play up to plus 200 points, which gives me 12 points for a win. Somehow it seems that the computer has been assessing the winner as if he has won games against players 400 points higher.Note that there is only a 300 point window for the class.
I had assumed that it was a new player, or a new player name being classed too low, but the points gained didn't seem to be reducing through the tournament as the computer should have been working out relative strength. Any ideas?