Stack Exchange, the company behind Stack Overflow, the influential-among-programmers Q&A site, is taking another stab at a revenue model for the service by launching a jobs board for its users at the Launch Conference in San Francisco today. It's the first presenting company at this conference. (There is a live video feed from Launch on Ustream.)

Previously, Stack Exchange had charged for the hosting of "white label" Q&A sites, but that model didn't work. In April of 2010 the Stack Exchange sites became free. Influence of the Stack Overflow site (the biggest of the company's sites) then grew quickly' the site has 11 million programmers a month using it, CEO Joel Spolsky claims. Now the company is trying to turn the revenue stream back on.

Stack Exchange is launching Careers 2.0, a job board for developers, with an emphasis on helping hiring managers find programmers with good reputations among other programmers. In other words, the top users of Stack Overflow.

Careers 2.0 profiles include a lot of data showing the job seeker&39's rating on Stack Overflow. (Image edited to showcase ratings features' click on image for original screenshot.)

The business model for Careers 2.0 is not uncommon for a recruiting service: it's free to use for people looking for jobs, but those doing the hiring pay for access. People pay not by the job post, though, but just by length of access. One week is $500, for example, which "ought to be enough to find a good programmer," Spolsky says. There's no free trial, but there is a money-back guarantee if a customer can't find a good candidate, he adds.

What makes Careers 2.0 interesting is that it illustrates the growing importance of online reputation for job seekers' see also Honestly.com. Also, it shows how any site that helps users create a professional reputation might be able to make money, at least until its users start including verifiable reputation scores in their resumes, thereby saving recruiters the expense of paying for resumes sorted by reputation. But we're getting ahead of ourselves.

There is a lot to be said for getting a form of peer review alongside a resume or job application. It is exactly the information a hiring manager might want and precisely what isn't available in any reliable way today. Recruiters can find candidates' managers can interview them' but you can't really know what a person's real contributions are unless you have an uncommonly good network of people that include the candidate's coworkers at previous jobs.

Spolsky says that Q&A sites like his are even good for wallflower employees--people who might not be very visible to others or who might have sparsely-populated profiles on people-rating sites like Honestly or LinkedIn. He says that with only three or four good answers, a technical professional can earn an impressive online reputation. Also, Spolsky says, people who are trying to scrub a damaging online search engine result might find that participating in Q&A sites is a very good way to rise in the rankings and push older misinformation or personal attacks off the top of the search results.

Unless people start gaming the reputation scores on Q&A sites in a sick form of job-hunting Survivor ("I'd better not rate Joe's answer highly, I might want the same job he'll be up for some day"), managing online reputation on sites like Stack Exchange and Quora could become a key career-building skill.