Updated 4:30 p.m.: Added a response from Google.

Google and Microsoft are at it again.

The battle between the two tech giants has once again spilled into public view on Twitter, this time over mobile patents.

It started Wednesday, when David Drummond, Google’s chief legal officer, wrote a blog post that accused Microsoft, Apple and other companies of trying to take down Google’s Android operating system by waging a patent war. The companies beat Google in a bid to buy Nortel’s patents last month and are now buying Novell’s patents.

Android’s success, Mr. Drummond wrote, has yielded “a hostile, organized campaign against Android by Microsoft, Oracle, Apple and other companies, waged through bogus patents.”

“Patents were meant to encourage innovation, but lately they are being used as a weapon to stop it,” he wrote.

But that’s not exactly true, Microsoft was quick to point out. Brad Smith, Microsoft’s general counsel, took to Twitter to say Microsoft asked Google to join it in bidding on the Novell patents but Google declined.

“Google says we bought Novell patents to keep them from Google,  Mr. Smith wrote. “Really? We asked them to bid jointly with us. They said no.”

Then Frank X. Shaw, Microsoft’s head of corporate communications, who has been known to pick fights with Google on Twitter, joined in. He posted a polite e-mail message from Google’s general counsel, Kent Walker, to Microsoft’s Mr. Smith declining to join Microsoft in a bid for Novell’s patents, accompanied by this note: “Free advice for David Drummond – next time check with Kent Walker before you blog. :).”

Late Thursday, Mr. Drummond added an update to his blog post.

“A joint acquisition of the Novell patents that gave all parties a license would have eliminated any protection these patents could offer to Android against attacks from Microsoft and its bidding partners,” he wrote. “Making sure that we would be unable to assert these patents to defend Android — and having us pay for the privilege — must have seemed like an ingenious strategy to them. We didn’t fall for it.”

Patent lawyers who are not involved in these cases said they often advise clients to avoid joint agreements for patents because they can render the patents meaningless unless all the patents’ owners agree on the same course of action.

For instance, if Google and Microsoft jointly own a patent and a third party wants to sue Google, Microsoft could theoretically license that patent to the third party and Google would lose its protection from that patent.

Mr. Drummond’s rant is along the same lines as the one Mr. Walker made when he announced that Google was bidding $900 million on Nortel’s patents, not so much for the technology as to protect against frivolous patent lawsuits.

That continues to be a huge issue in the tech world. But for now, attention has been diverted to Microsoft and Google’s tit for tat. We’ll see who lobs the next attack.

Article source: http://feeds.nytimes.com/click.phdo?i=6e8f35c18649c509c5dff6b9a372d6f2