Sifting through the nine patents cited by Microsoft in its patent-infringement lawsuit against Salesforce.com this afternoon, one in particular stands out as an example of just how basic these types of things can get.

It's U.S. Patent No. 5,845,077, issued to Microsoft on Dec. 1, 1998, under the title, "Method and system for identifying and obtaining computer software from a remote computer." Here's the abstract.

Creators of computer software provide the most up-to-date versions of their computer software on an update service. A user who has purchased computer software calls the update service on a periodic basis. The update service automatically inventories the user computer to determine what computer software may be out-of-date, and/or need maintenance updates. If so desired by the user, the update service computer automatically downloads and installs computer software to the user computer. By making periodic calls to the update service, the user always has the most up-to-date computer software immediately available. The update service may also alert the user to new products (i.e. including new help files, etc.), and new and enhanced versions of existing products which can be purchased electronically by a user from the update service.

Of course, that method of software updating may have been novel when Microsoft applied for the patent back in November 1995. And this statement is not meant to pass judgment on the merits of the patent, positive or negative. But you'd be hard-pressed to find a savvy PC user today who would find that type of mechanism particularly innovative. It's commonplace.

And the irony here is that it's the type of approach that initially differentiated "software as a service" vendors such as Salesforce.com from Microsoft's traditional software.

"The secret to Salesforce.com's success: the speed with which it can update its software," explained BusinessWeek in a 2005 article. "Microsoft last updated its original CRM software in January, 2004, with plans for a new version in first quarter, 2006. Meanwhile, Salesforce is constantly fixing bugs and adds features without interruption to the customer or added expense."

For whatever it's worth, much has changed since 2005, with Microsoft offering a version of its Dynamics customer-relationship management software as an online service of its own, attempting to compete more directly with Salesforce.

The eight other patents in the Microsoft suit deal with a variety of underlying web and computing technologies, including "Method and system for mapping between logical data and physical data," and "System and method for providing and displaying a web page having an embedded menu."

Salesforce declined to comment on the Microsoft suit.