In the enterprise world, this is known as "lead generation", and these queries for specific items would be "qualified leads" (meaning the buyer has specifically expressed interest in the type of product you're selling). It is a very profitable segment of the industry. That said, there are an awful lot of problems bringing the model to consumer goods.

The instant gratification problem that naval pointed out in the comments...Most folks have a buying process something like: Want, shop around for a few minutes to a few hours, buy, have it within a week. Sometimes it includes going to see it in person at a brick and mortar. Waiting for a bunch of people (most of whom will be spammers) to submit proposals, is tedious and boring...like being at work. A lot of enterprise product buyers even try to avoid that process. I have a Dell small business sales rep, who usually gets me better prices than the website, but I rarely go through him because the process is tedious. It wastes more of my time than the money I save. I imagine if I were buying dozens or hundreds of machines, it would begin to be worth it.

The spam problem is always underestimated by people who don't deal with it professionally. By the time Scott Adams sees the spam problem in his own life, it has already made it through several anti-spam preventative systems. This is a new way to spam, and will require new ways to fight it. I suspect one of the lead generation models would have to be used...as dpatru suggested, vendors paying a small amount to be displayed to the user would be a good path. A vendor would probably happily pay a few pennies, or even dollars, to reach someone that they honestly believe would be a good fit for their product. In the enterprise world, you only need a few vendors, a few buyers, and very expensive products, to make the model profitable. In the consumer space, you need all the vendors to make consumers really happy, and an awful lot of consumers to make it worthwhile for vendors to monitor and respond to leads.

It's an interesting take on how vendors in this highly distributed world can find out what people really want. Chinese manufacturers make almost everything we buy these days...but what items people need and want, fashion, trends, perception of quality and beauty, are different across cultures.

But, I don't think it will win out over automated recommendation and search engines. Automated tools will get better (and have gotten dramatically better in the past ten years) at helping folks find the right items. Amazon is already pretty darned good at it...I usually know which of a handful of items in a genre I want within a few minutes of beginning my search. At worst I read a few reviews, and then know. The Amazon model has the benefit of having other customers telling me about the products...I have a deep mistrust of companies telling me about their products. Some are honest and tell you exactly what you need to know, but most are hyperbolic to the point of being nonsensical.

In other words, this is one of those ideas that sounds neat, and is a really interesting thought exercise, but I really doubt I would ever use such a service, as a buyer or a seller.