Rackspace has teased a preview page for a SaaS marketplace called AppMatcher. (It looks to be more of a front-page mock-up than anything actual; note that the “1,000 apps”, “100,000 businesses” bits look like placeholders.) The concept is pretty straightforward: app providers provide info about their target customer, and potential customers provide info about their company, and the marketplace tries to hook them up.

Hosting companies have increasingly been talking about doing marketplaces for their customers and their partner ecosystems, particularly in the SaaS space, and Rackspace’s foray is one of several that I know of that are still under wraps. Parallels has gotten into the act on the small business end, too, with the SaaS marketplace it’s integrated into its software. And a ton of other companies in the technology services space are also wanting to jump into the SaaS marketplace / exchange / brokerage business. (And you have folks like Etelos who build software to enable SaaS marketplaces.)

We’re seeing other software marketplaces in the cloud context, of course. For instance, there’s the increasing trend towards cloud IaaS providers offering an app store for rent-by-the-hour or otherwise cloud-license-friendly software — an excellent and important convenience, even necessity, for really driving cost savings for customers. And there are plenty of opportunities, including in the marketplace context, to add value as a broker.

However, I suspect that, by default, these days, if you have a need for software that does X, you go and attempt to enter X into Google, and pray that you’ve picked the right search term (or that the vendors have done reasonable SEO), in order to find software that does X. Anyone who wants to do a meaningful matching marketplace needs to be able to do better than this — which means that the listings in a marketplace need to be pretty comprehensive before it offers better results than Google. What a marketplace offers to the buyer, hopefully, is more nicely-encapsulated information than raw search results easily deliver.

However, many SaaS apps are narrow, “long tail” applications — almost more a handful of features that properly belong in a larger software suite, than they are properly full products unto themselves. That means that it’s harder to make sure that you really have wide and deep listings, and it means that useful community review gets more difficult because the app that’s got a handful of customers quite possibly doesn’t get any thoughtful reviews. And for many of the companies that are considering SaaS marketplace, the length of the long tail makes it difficult to have a meaningful partner model.

So what does Rackspace have that other, previous, attempts to launch general SaaS marketplaces have not? Money to do marketing. And at least thus far, the apparent willingness to not charge for the matching service. That might very well drive the kind of SaaS vendor sign-ups necessary to really make the marketplace meaningful to potential customers.