If it’s Tuesday, it must be time to blog about tech firms taking competitors to court for alleged abuses of their intellectual property. This week’s contestants include two vet­eran practitioners of the art, Microsoft and Apple. ­

Microsoft’s move is more offensive: On Monday, it sued Barnes & Noble and two Taiwanese manufacturers, Inventec and Foxconn, for infringing on five patents in the Android software used in B&N’s Nook e-reader tablet. This is the latest step in Microsoft’s strategy of targeting licensees of Google’s operating system--instead of Google, which would have directly infringed on any patents by writing Android in the first place--last seen in October, when it sued Motorola on the same general grounds.

As usual in this sort of case, Microsoft can’t be bothered to document the allegedly infringed patents in its press release or blog post by vice president and deputy general counsel Horacio Gutierrez (an omission quickly called out in the uniformly derisive comments on the latter). But PC World’s Tony Bradley obtained a list from Microsoft PR for your consideration.

They are: 5,889,522 (“System provided child window controls,” or having the operating system help programs to display secondary windows); 5,778,372 (“Remote retrieval and display management of electronic document with incorporated images ,” or having the browser download and display text before images); 6,339,780 (“Loading status in a hypermedia browser having a limited available display area,” or having the broswer only show download status while the page hasn’t finished loading); 6,891,551 (“Selection handles in editing electronic documents,” as in an interface for selecting, copying or cutting text); and 6,957,233 (“Method and apparatus for capturing and rendering annotations for non-modifiable electronic content,” or taking notes on a read-only document).

All of them are begging to be thrown out on the grounds of non-obviousness or prior art, but especially the second, third and fourth patents. Note, also, that the ability to select, copy and cut text remains unavailable in Microsoft’s Windows Phone 7 software. Nothing says “we can’t keep up in the market” quite like suing competitors for offering features absent from your own product.

No, massive industry-wide licensing of Microsoft’s patents is not the solution, as Gutierrez’s post asserts. Throwing out ill-founded software patents is the solution. Until that happens, Microsoft may collect some extra royalty fees from companies like Amazon and HTC that find it easier to settle than to slug things out in court. But the company certainly won't be earning any respect for this move.

Apple’s venture into intellectual-property litigation isn’t as objectionable as Microsoft’s--it’s not trying to tax an entire segment of the mobile ecosystem. But it has its silly moments, too. On Friday, the company sued Amazon for naming its new software shop for Android phones the “Amazon Appstore.” The Cupertino, Calif., company contents that Amazon’s use of that moniker “will confuse and mislead customers.”

No it won’t. Or, to be more exact, it won’t befuddle anybody who wouldn’t also be confused if Amazon called this collection of Android programs its “App Shop.” Unfortunately for Apple, “app store” has become a generic term in everyday speech for any centralized one-click program-download site. Amazon could label this thing the Byte Bazaar or the Software Souk, and people would still call it “Amazon’s app store.”

The rules are different for companies employing a particular brand name in their business, and Apple may have a respectable case against Amazon for using such a similar moniker. Microsoft has had years of success defending its trademarked term Windows, despite that being an utterly commonplace description for a fundament element of computer operating systems.

Apple obtained a trademark for “App Store” in 2010, although Microsoft has been challenging that (most recently, it asked to have an Apple filing struck for using a too-small font). As for the one-word variant used by Amazon, “Appstore,” Saleforce.com sought a trademark on that in 2006 but gave up in 2008.

My bet is that Amazon adopts some barely different brand name--like, say, App Shop. (Note to Amazon legal: My licensing terms are quite reasonable!) And that would be an acceptable outcome... provided Apple doesn’t then sue those who use “app store” as a mere description or claim ownership of any combination of “app” and a synonym for “store.” Knowing how these legal strategies have unfolded the past, I can’t rule those things out.