Amazon.com apparently believes the best defense is a good offense. In response to a patent infringement lawsuit filed by IBM, the online retailer on Thursday launched several counter-claims against the computer maker, charging that IBM has stolen Amazon intellectual property.

"It is actually IBM that is using Amazon.com's technology without permission, not vice versa," Amazon alleges in court documents.

IBM sued Amazon in October in the U.S. District Court for eastern Texas. IBM claims Amazon's online customer recommendation system, as well as several other features on its popular Web site, violate IBM patents governing a broad swath of e-commerce techniques.

Amazon claims it is actually the innovator. "IBM more recently has sought to follow the lead of Amazon.com and other innovative Web companies by expanding its offerings into Internet technologies. In doing so, IBM has relied on Amazon.com's innovations without regard for Amazon.com's patent rights," Amazon claims in the court filing.

Among other things, Amazon claims IBM's WebSphere and other middleware products infringe on intellectual property rights granted to the company by patents that govern "a system and method for refining search queries" and a "method and apparatus for structuring the querying and interpretation of semistructured information."

Amazon also claims that IBM customers that use WebSphere are violating its patent rights. WebSphere is used by thousands of businesses in the U.S and throughout the world and accounts for a significant portion of IBM's revenue.

Amazon.com also accuses IBM, the world's second largest technology company, of acting like a fly-by-night patent troll for buying up patents, and calls the vendor a technological dinosaur that "has never been seriously recognized for providing the nimble, fast-paced developments and services needed to offer innovative e-commerce."

Amazon is asking the court for unspecified damages and an order that would prohibit IBM from continuing the alleged infringement of its patents.