Experts Exchange
http://www.experts-exchange.com/

"An open marketplace where IT Experts compete and collaborate with each other in order to provide specific solutions to specific problems"

This site doesn't show gurus giving step-thrus to neophytes. It's for experts who want to trade with each other. Since 1996 the site has built up tens of thousands of users. Their big database is quick.

They've invented a currency of "question points" and "expert points" to account for the transaction and keep it focused on specific answers to specific questions.

To browse their previously answered questions you have to register and let them check out your email address, but they're expert enough to do the whole rigamarole instantly. Once in, you have to pay your question points to look at answers at ten per cent of their original cost, but they give you some points to start with. Even a quick browse shows serious people getting specific answers fast.

It's a free service. Sellers earn points they use to buy answers.