How can you tell the difference between a men's snowboard and women's snowboard?

The guy named '?' is right. Most of the time the only difference is that the graphics are more feminine for girls and also sizes vary. Some brands, however, are actually taking mens boards construction and specs and altering them to make it more women friendly. An example: The k2 Duchess. It is based off the mens snowboard, WWW(world wide weapon), but has specs like intruded base instead of sintered because its easier to repair.....(who knows why women would be repairing their boards more often, but whatever). It has a little more aggressive side cut so that women can turn more smoothly because alot of women aren't real aggresive riders like some men can be. It's designed for a more smooth, floaty ride. Much less bouncy. Anyway, some women use mens boards. Most dont have much for difference. I've ridden a mans board before. Loved it.

About 5-7 years ago (depending on the brand) this all changed for the better. Women are a huge portion of the market these days, and most brands are using female specific cores, and are laying up the boards with lighter tensioning and laminate schedules. That means better flex zones based on the narrower expected stance positions, lighter weigths, etc. The days of painted up guys boards are over.