They don´t have to post, just vote. The girls are trying to do something "for the girls" but it is obviously not worth doing anything it if no one is interested. Whether it is a realistic figure of how many girls visit the site or not, they are trying to find out how many girls are out there and are wanting to be involved in things a bit more.
Either vote or miss out, stop being so negative. FerretGirl and Toadette have said nearly nothing for a year but now are wanting to be involved more. There must be more like them!