In the latest of several swipes against patent trolls, Google has taken aim at the companies who sell off their patents so they can be used in lawsuits. Writing to the FTC and US Department of Justice, Google warned against "patent privateering" — by which it means outsourcing patent warfare by going through firms that don't make anything themselves and therefore can't be countersued. Patent trolls are almost universally reviled for aggressively suing companies on vague, sweeping patent claims. But Google claims the US government should turn its attention to the companies who created those patents in the first place.

"PAEs [Patent Assertion Entities, which litigate patents] impose tremendous costs on innovative industries," writes Google in a letter co-signed by BlackBerry, Earthlink, and Red Hat. "These costs are exacerbated by the evolving practice of operating companies employing PAE privateers as competitive weapons." That's partly because patent assertion entities can be overly aggressive, but also because using them can create layers of fees and companies that must be navigated to license a patent. Google didn't name names, but it linked to an article citing both Microsoft and Nokia as companies that employed privateering.

In late February, Google complained that the current patent system overvalued the initial process of coming up with a patent idea while burdening people who were able to actually implement it effectively. Last month, it took steps towards a licensing schema that it hoped would promote the effective and responsible use of patents. It's also pledged not to sue open source developers "unless first attacked," asking other companies to do the same.