Black's problem piece in the Exchange Variation of the Queen's Gambit is the bishop on c8. The point of 6.Qc2 is to embarrass the bishop by taking away its best square: Eric's 6...g6 is a radical attempt to solve the problem. (I've tried it more than once myself: NM Steve Tennant swept me off the board at a Western Open some years ago from the position after 8.Qb3, which forces Black to weaken the queenside pawns slightly.)
FM Jorge Peleaz really played a model game with the White pieces. Once the hanging pawns are forced into the unfavorable c4-d5 formation, the bishop on e6 is much less powerful than the dancing knight. 46.f5! is real purty.
If Black can find a way to get away with this line, the 6...g6 idea is golden. Until then, there's always 6...Be7.
