I think their "Why" section addresses this pretty well: they believe one of the underlying reasons there aren't more women in tech is the lack of visibility for

I think their "Why" section addresses this pretty well: they believe one of the underlying reasons there aren't more women in tech is the lack of visibility for women already there: young women see a male dominated field and feel like they're not welcome, and so perpetuate the problem. By highlighting the existing women in tech, more young women will feel welcome there.