In his Sunday column this week, colleague Dan Gillmor touches on Google’s potential influence on the classifieds ads market and its ability to lure single-item sellers into its ad network.

But there’s another force, some believe, that could help reshape the classifieds ads model. The ability of web site owners to publish feeds of their content, known more commonly as RSS, could soon allow sellers and buyers, or employers and potential employees, to more efficiently find each other.

Consider XYZ Corp., which wants to hire five programmers. Its human resources team can place ads in newspapers and with Internet jobs sites Monster and Career Builder. Or, for free, it can create a constantly updated jobs feed that individuals can subscribe to with their aggregators, and that search engines can index and make available for searching.

Former Overture Services and Knight Ridder Digital executive Tony Gentile and Scott Rafer, CEO of Feedster are among those who have promoted the idea. Rafer, in fact, is testing a service at that allows users to scour RSS feeds for job listings.

Rafer says the Monsters and Career Builders of the world may someday become largely irrelevant once companies create RSS feeds of their job listings. will not be able to make money on listings in the same way they do now. Instead, their revenue may come from offering fee-based services — such as background checks on potential hires — that complement the listings and tap into their expertise about the jobs market. (Clarification via Scott.)

“Really what’s going on is, if you have all the job postings, ads, whatever, people have to come to you,” he said. ”What we’re seeing is a world where if you want to see all the software jobs east of the Mississsippi, I can aggregate that and give it you cheaply.”

The concept extends beyond job listings. What about individuals who want to sell their furniture or digital cameras? Today they go to craigslist, eBay or the local paper.

But what happens when they begin publishing their own classified ads on their own web sites? Blogging tools make it a cinch for anyone to quickly and cheaply become a publisher and instant advertiser. In the new world order, they could post their classified ads on their blogs and wait for a Feedster or Technorati or Google to scoop up the XML feeds, categorize them, and make them find-able by anyone on the Web.

“An XML feed for anyone who wants one,” Rafer said. “This puts Monster in a new position. It puts eBay in the buyer insurance business, or something other than the listings themselves. It’s exactly why web services exist.”

Taken further, the concept would allow people on both sides of the transaction (buyers and sellers, recruiters and job-seekers) to publish ads. A smart search engine would automatically notify them when it finds the right matches (think Semantic Web ).

Craigslist has taken a first step in training people to view aggreagtors as gateways to classified ads. The site offers RSS feeds for most categories, and founder Craig Newmark said the feeds get about 200,000 hits a day (most from MyYahoo, interestingly enough).

Newmark isn’t convinced that most people want much more than that.

Newmark says that as technologist and computer programmer, the concept that Rafer and others promote appeals to him. But as a businessman who has watched the habits of his users for 10 years, he is not convinced most people want to take on the responsibility of publishing their own ads.

“I can see trends in that direction,” he said. “The idea is that people will post all sorts of things on their their personal web pages or blogs with personal profiles. But people don’t seem to care that much about having their personal place on the web…What people want is a combination of simplicity and trust.”

Newmark noted that many companies already provide RSS job listings. But in practice, he said, most people still like coming to centralized job sites.

Stay tuned.