this is Google's actual legal reasoning as to why they shouldn't be held liable for contributory patent infringement in Oracle v. Google:

"[S]ection 271(c) applies only to offers for sale, sales, and importation, but Google does not sell, offer to sell, or import Android or Android SDK. [...] The ordinary meaning of 'sale' requires transfer of ownership for a price. [...] Android and Android SDK are offered free of charge to anyone who wishes to download them off the Internet, however, and there is no evidence that Google ever receives any consideration in return. That undisputed fact precludes a finding of contributory infringement."

http://fosspatents.blogspot.com/2011/08/oracle-v-google-upda...