Apple is appealing to the U.S. Patent and Trademark Office, saying that Microsoft is "missing the forest for the trees." By that, Apple means to say that Microsoft is ignoring the fact that Apple's App Store is generally understood as a proper noun. If their own "App Store" moniker is unworthy of trademark, then Microsoft's "Windows" is equally so.
To give the following excerpt some context, we should tell you that "genericness" is the extent to which a trademark applies to the general nature of the product, making a "generic" trademark less valid: "Having itself faced a decades-long genericness challenge to its claimed WINDOWS mark, Microsoft should be well aware that the focus in evaluating genericness is on the mark as a whole and requires a fact-intensive assessment of the primary significance of the term to a substantial majority of the relevant public," said Apple.
That wordy legalese argument just means that a trademark can only be deemed overly generic if the public predominantly believes that the potential trademark refers to a general type of product. Apple cites the testimony of a linguistics expert, who says that "the predominant usage of the term APP STORE is as a proper noun to refer to Apple's online application marketplace."
In a previous filing, Microsoft keenly pointed out that Apple's own Steve Jobs has used the term "app store" to refer to other OS' marketplaces. As is the case with a ubiquitous term/trademark like "Kleenex", Apple's trademark issue is a chicken-and-egg scenario, where the term only became generic after it had been trademarked. What do you think? Should Apple rename their App Store to something like "iApps"?
source: TechFlash via CrunchGear