When you finish a game (or go to a game in your games archive) there's a link in the game page above the moves list saying "Computer Analysis", click it and you'll get a message back in an hour or so with the analysis. This only is available for live games and online games, not just when you start messing around with the computer on "Play"... 'Vs. Computer".
Computer analysis
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In the overview of functionalities is mentionned : unlimited analysis of your games.... Where is this functionality hidden??