I've tried most of these paid to socialize networks, the idea is that they act as places for people to gather, the money is made in the followings ways

1. the websites are affiliated with advertising, they earn a commission for any sales made via people clicking on adverts - a site like yuwie for example uses incentivized clicking, a rewards system to encourage the ads to be clicked on by their website visitors - the reward is something like a penny or less - so that isn't a way for the visitor to earn a living.

2. Yuwie also have an area where visitors can advertise their wares, this is a way a visitor could make money.

3. the third way is to build up a list of contacts via networking and connect with them on many networks, like social networkers do - repeat exposure to personal branding being a source for revenue, once your contacts have double opted into your lists via e-mail courses, blogs or whatever content they want more info on in a newsletter/update.

The down side with yuwie is the lack of training affiliates receive, the idea that you can make big money by clicking on adverts/signing up to dubious offers - and I say dubious rather than illegal as the type of offers yuwie promote are the same type that I've seen on places like hotmail, google, yahoo, facebook if they were illegal then it would mean every major business was a criminal - so for my own sanity - yuwie,facebook,microsoft etc are as ethical as each other the actual level of dubiousness as yet undecided.

So the sites make money, just not in quite the way the advertising suggests.