When it comes to consoles, game selection (and quality of said games) really is everything. No matter what the hardware specs of the console are, no matter what other tricks it can do, people buy a console, for the most part, to play games. That is something Nintendo fully understands, and as such it seems they company is planning to more than double the current library of games for the Wii before the end of 2Q 2007. That would mean at least an additional 45 games, an impressive feat for only a few months time.
Obviously, they have many developers producing games for the console, and likely a lot of the titles aren't going to be just for the Wii. However, having nearly 100 separate titles available in less than a year from release is impressive, and will probably only serve to increase their sales. The Wii, while still falling short of the mighty PlayStation 2, is currently outselling the other two top consoles each month.