"Microsoft and Amazon.com have reached an agreement that gives
each company a license to the other's patent portfolio, in a way
that could revive one of the Redmond company's longest-running
controversies. That's because, as part of the deal, Microsoft says
it's granting Amazon patent-related "coverage" for its use of
open-source and proprietary technologies in its Kindle e-reader,
and its use of Linux-based computer servers.
"One practical effect of such cross-licensing deals, as they're
known, is to head off potential patent disputes. In that way, the
agreement amounts to a peace accord between the companies. At the
same time, the deal could raise eyebrows in some corners of the
technology world, if it's interpreted as Amazon implicitly
endorsing Microsoft's claims that Linux and other open-source
technologies violate its patents. Open-source advocates have long
disputed those claims."