Girls and young women are now the most prolific web users
technology.timesonline.co.uk
technology.timesonline.co.uk
Guys use these sites heavily until they find a girl (with or without the help of these apps.) Then, their usage drops off considerably. Girls use these sites primarily for other reasons so their usage never really has a reason to drop off.
For a long time my wife wouldn't use ourdoings.com because it's always easier to just get me to put our photos up. But now that we have a wifi photo frame, she's become active so she can tweak which photos go to the frame and which don't. I have other female users, but this is the best feedback loop I've got.