cervelo says WSD is bogus, there's only spsd (short people specific design) - go figure.
I'd agree with that...mostly. Short women definitely have fit issues that are different than the average-sized rider, and so do short men. A well-fitting, well-handling frame requires someone who is intimately familiar with designing frames properly around the small folk--whether they are male or female. Crucial design elements like BB height, head angle, seat angle, fork rake, wheel size, even the positioning of braze ons..all must be considered in a different way than when designing a frame for a larger rider.

"WSD" simply means it will have a shorter reach, which for a lot of small women really helps (especially since most "unisex" stock bikes in the small sizes have a disportionately long reach), and perhaps a higher head tube height. Both these elements are generally appreciated by smaller women, but it does not necessarily mean WSD will work for all women. Generally, it benefits those whose torsos are short relative to their inseams.