Every now and then a product comes along - either from a startup or as a project within a larger company - that seems to meet a worthy need but just doesn't find its legs. Sometimes great ideas are pushed on us too quickly, or are ahead of their time, and other products capitalize on this market months and years down the road. As senior associate Andrew Parker pointed out Wednesday on his blog The Gong Show, this is precisely what happened with the Q&A service boom we see flourishing today.

These days, services like Quora, Facebook Questions and even more specifically, StackOverflow, are almost a dime a dozen. Many exist, but only a handful have actually garnered a loyal and significant user base. But how is this possible when Q&A has been around for so long? Why now is it so much more popular?

"In short, paying someone with fungible reputation has proven to be more motivating than paying someone cash, in the Q&A sector."
- Andrew Parker
In April of 2002, Google launched Google Answers, an online Q&A market where users could be rewarded with actual cash for their ability to find information online. Eventually, Google shuttered the product and others popped up in its place, including Yahoo! Answers which still lives on today. Now, the Q&A craze is in full swing, so why did Google fail early on?

"Google assumed that you had to pay people for high quality answers to domain-specific questions, but it turns out people will willingly give away copious cognitive surplus in exchange for social credibility amongst their peers (points, badges, leaderboards, etc)," says Parker. "In short, paying someone with fungible reputation has proven to be more motivating than paying someone cash, in the Q&A sector."

We now live in an era - ushered in by the likes of Foursquare and Farmville - where we cherish not monetary reward, but geek street cred. Badges, stickers, points, etc. People provide their knowledge on Quora partly to boost their own repuation in an area, and users battle to be "gurus" of various topics on GetGlue.

All of this and no monetary compensation. While these startups have leveraged this trend, Parker points out it's not as simple as "if you build it, they will come."

"The successful Q&A sites have proven that users can be better motivated without financial incentive, but constructing the incentive mechanics is the (relatively) easy part of the equation... the difficult part is building a community that actually cares about you," he says.