Maybe this forum post helps:
http://www.chess.com/forum/view/chess-openings/anti-dutch-2-bg5quot
or:
http://www.chesspub.com/cgi-bin/chess/YaBB.pl?num=1294843056
It appears that this is an offensive line, not suited for play against grandmasters, but extremely useful in on-line, quick amateur play. Definitely worth studying a bit if you continue to play the Dutch (and you should, it's a great opening as it is not used that often, and you can get amazing results and fun, agressive games).
what are you supposed to do if your opponent does bishop g5 2nd move? are you supposed to fiechetto your dark square bishop, or do Nf6, and risk the pawn structure for the bishop pair. Or something entirely different?