TomTom has countersued Microsoft, claiming that the software giant's Streets and Trips program infringes on four TomTom patents.

The suit, filed on March 16, presents a twist to the suit that Microsoft originally filed in February, claiming that TomTom infringed several of its own patents. That suit also called into question the nature of open-source software, as two patents involved what open-source advocates called Linux-specific patents, rather than proprietary TomTom code.

Now, both sides will have to fend off the other in open court, at least if the suits go forward. But does Microsoft need the anti-Microsoft sentiment at this point in time?

Read the rest of this story at eWEEK: "TomTom Countersues Microsoft for Patent Infringement"