Microsoft says that the US Patent and Trademark Office (USPTO) has agreed to hear Microsoft's argument that the Eolas browser plug-in patent is invalid. Microsoft had previously lost a landmark $521 million verdict in the up-again, down-again patent battle with Eolas. That verdict was eventually thrown out by an appeals court, but the USPTO later upheld the validity of the Eolas patent, though only Eolas was allowed to submit evidence before that determination was made.
Microsoft has been fighting the Eolas patent since 1999. Now, Microsoft says that the USPTO will hear its argument that it, and not Eolas, is the inventor, and thus the owner, of the browser plug-in technology in question. A five-judge panel within the USPTO will weigh evidence from both sides about the patent's validity and ownership. According to Microsoft, the USPTO has already acknowledged that Microsoft owns an earlier if more general patent that covers the same subject as the Eolas patent.
The Eolas patent describes a method for automatically invoking an embedded program object, or what's more commonly called a plug-in, from within a Web browser. Eolas charged that Microsoft's implementation of ActiveX plug-ins in Internet Explorer infringes on this patent. As a result, Microsoft changed the way that IE handles plug-ins, inconveniencing hundreds of millions of customers in the process.
Don't expect any quick decisions by the USPTO. Microsoft first made its prior art claim to the agency in January 2006, almost a year and a half ago. The company expects the USPTO to rule on the validity and ownership of the patent within a year.