In a clear move to undercut one of Google's most noteworthy revenue sources outside of advertising, Microsoft today launched its "search server" strategy by releasing both a free and a commercial version of software that performs many of the same functions as a dedicated search appliance.

In classic Microsoft fashion, the company has released a free edition of the product as its way of crashing the gate.

"Our aim for Search Server Express is to give you a free and powerful enterprise search product that's incredibly easy for you to deploy," reads a message from Enterprise Search General Manager Jonathan Kauffmann to his team's blog this morning. "After you download it, you'll find it takes just a few minutes to get it up and running. It's going to be the fastest way you can bring an enterprise search experience into your business."

Also in classic fashion, the Express edition will be shipped as part of Office SharePoint Server 2007, giving Microsoft's search strategy a foot in the door of many organizations automatically.

Microsoft Search Server 2008 generates network-wide indexes on a company's existing server equipment, rather than on new server appliances such as Google's or Thunderstone's. These indexes can be used as an infrastructure for internal query pages, giving employees a tool for natural-language searches deep into the matrix of their internal documents.

But while Microsoft repeatedly used the phrase "out of the box" to describe many of the features of the free Express edition, some careful parsing of that phrase may point you to a different box than you might have expected. While a search tool or appliance is capable of accessing data within individual documents, typically out of the ordinary box, for it to access the information within databases and repositories, it needs a kind of software driver called a connector. Among Microsoft's "sample connectors" are drivers that enable indexing of Exchange public folders and SharePoint sites.

Enterprises use content management systems like EMC Documentum and business document services such as Lotus Notes and IBM FileNet repositories. Getting access to those is what generally distinguishes an "enterprise class" product from one that merely indexes document files. And here is where Microsoft's product starts evolving out of "Express" territory, and toward the commercial side.

"We believe Microsoft and its partners can offer you the one-stop search experience you've been looking for," Kauffmann's message continued, "and today, companies like EMC, Cognos, HP, Business Objects, SAS, and OpenText have already announced their intent to support federation with Search Server and Search Server Express. We expect many of them to release federated search connectors to coincide with the release of these products in the first half of 2008."

Other distinguishing factors between the Express and commercial editions include that the commercial Search Server 2008 is not limited to a single server per seating, and can be adapted to a larger server cluster. Availability, load balancing, and failover policies are added to the administration tool of the commercial edition.

By comparison, Google's search appliance does appear to maintain, shall we say, a "barrier to entry." Its entry-level Mini search appliance currently sells for $1,995, though even then, it uses individual "enterprise connector" software add-ons to access repositories such as Documentum. Google's appliances are also sold on an indexing scale, on which its Mini tool is limited to 50,000 documents, while its $9,000 edition is set up to index 300,000 documents.

Neither the Express nor commercial editions of Search Server 2008 have set document limits, boldly sticking it to Google's entire business model for hardware. If all goes according to Microsoft's plan, IT departments could find themselves asking some familiar questions: Is Microsoft's alternative qualitatively better than the industry leader? And if it isn't...will it matter?