I agree, its not overbearing and its clearly well targetted...
I have actually pre-ordered the DS version of the game, I really hope its a good version, I've wanted some decent portable chess game for a while now, and am putting my faith (somewhat foolishly) in the idea that this will be similar in style to the PC engine games.
Thought the ads would be annoying, but I actually liked the Chessmaster Ad banner. Very nicely done.
May be I am biased because I am planning to buy this software (this would be my first paid Chess software).