Microsoft is suing TomTom in part because the guys from Redmond claim that TomTom's use of Linux in its navigation devices has violated three of its file-system related patents. One reason why Microsoft feels it can do this is that it already has patent cross-licensing agreements covering these patents with other Linux-using companies.

According to Microsoft, Google's Android OS is infringing on many of its patents and hence those manufacturers who use Android for their devices owe royalties to Microsoft.

Everybody's suing everybody! ... None of the major companies really seem to take patents seriously. ... And why should they take patents serious? The United States Patent and Trademark Office grants patents for vague ideas, obvious processes and usage models and even the most mundane software user interface conventions.

TiVo's shift to a strategy of patent litigation is not paying off, patent trolling becomes common, Microsoft rides the wave

Acer is suing Hewlett-Packard again for patent violations. It's an escalation of the battle over the two companies' intellectual property that began earlier this year.

In the old "pre 2000" day, the objective of most technology companies when they applied for patent protection was to ensure that their products and technologies were not copied by their competitors. The idea was that thanks to the patents you enjoyed about 20 years of exclusive use of your technology, after which everyone was free to use it because by then it was considered obvious.

Another pseudo-FOSS company is suing its rivals using software patents, this time targeting Apple and Microsoft

Companies that screw Free software by paying Microsoft for unnamed software patents grow even closer to Microsoft

Microsoft made waves this week with their GPLv2 contribution of virtualization code. On the other side of the coin, Microsoft continues to take issue with open source vendors over the issue of patents. One vendor that has called on Microsoft to be more open is Red Hat. In a blog post, Red Hat's legal team praised Microsoft's code contribution while asking Microsoft to change its stance on patents.