This settles it for me:
Q: Talk to me about the mizuage ceremony. What is it, and why is there so much confusion about it? A: This again goes back to the separation between the pleasure quarter and the entertainment quarter. Mizuage is really a coming-of-age ceremony, and apparently there was some selling of the virginity that went on in association with that ritual ceremony in the pleasure district a long time ago. However, that has never been true for the geisha. For the geisha, it was simply when they were becoming a young woman, similar to a sweet 16 in the West, and it was symbolized by the change in hairstyle, into a more womanly, grown-up hairstyle. And also certain subtle changes in the ensembles. There are a lot of rites of passage, but for some reason this one has been really latched on by people, and maybe it’s because of this misunderstanding. Also, it is true that as with many of the rituals and rites of passage, once one has become a maiko [geisha-in-training], or a geiko, it’s very expensive, because every time you go through an entire change of kimono, for example, or of hairstyle and you need different hair ornaments, these are expensive things. For me, I was the successor to the house, the atotori, so there was no question that the money was there to provide this. But if someone is coming from the outside and training, as basically someone who is there under contract, it is expensive, and sometimes they do ask their patrons to help pay for the cost involved in making the transition. Q: But their virginity isn’t offered in exchange for that help? A: That is never on the table. There is one other potential source of confusion, and that is with the word "mizuage" itself. In the Gion, the geisha district, and in many areas of the entertainment industry, "mizuage" is also a term that directly means "gross earnings," because it’s an old fishing term; as you may know, Japan was dependent on fishing for one of its main economic bases for many years. "Mizuage" means "to take out of the water." It stood for the catch. "What was your catch?" — "How much money did you make from the water?" So when I refer to mizuage, I’m actually referring to my earnings, rather than the ceremony itself.
It is from an interview of Iwasaki by Tamara Weider in the Boston Phoenix, the url for it is
http://www.bostonphoenix.com/boston/news_features/qa/documents/02473409.htm."
* Taken from
http://en.wikipedia.org/wiki/Talk:Mizuage#Sources