The rumour mill has it that Google is about to enter the fray with a classified listings product. The listings model, as popularised by Craigslist has been a persistent thorn in the side of both newspaper groups and eBay, which has of late been aggressively acquiring stakes in free classified players.

For Google, a key opportunity area is recruitment where vertical search engines such as SimplyHired are starting to make traction with their aggregated job listings combined with local search and social network integration. In a sense, Google has always been in the listings game. Adwords is nothing more than a paid listings directory redux.

This time round, the challenge will be offering job candidates and recruiters a mediated search experience that not only effectively matches market participants, but finds a clever way to price the value of the connection. Traditional job boards do a poor job of reflecting the underlying worth of market scarcity. If the market is running hot for Java programmers, it should cost more to advertise to them. Similarly, if corporate lawyers are a dime a dozen, you should be able to purchase a performance based campaign for those social undesirebles at a few cents a click.

Now, thats what I call natural justice.