The patent war over smartphones is a battle that has engaged the likes of companies such as Apple, Google, and Microsoft. However, as the media decides to focus primarily on these companies at the forefront of this patent war, many smaller companies, which hold an important place, don't get the same kind of recognition. One of these lesser known companies in this patent brawl is Nortel, a Canadian-based telecom company, that went bankrupt in 2009, but sold $4.5 billion dollars in patents to a group of companies - Microsoft, Apple, RIM, Ericsson, & Sony (all of these companies operated under the name "Rockstar Bidco"). The reason for buying this incredible amount of patents was to take on Google and its operating system, Android. The patents that were bought relate to search, advertisements, internet protocols, and graphical interfaces for navigational purposes.
The concept of patent privateering emerged from this concept of larger companies handing off patents to smaller companies that would pursue litigation for patent infringement against their competitors. Larger companies despise this practice because larger companies work in sort of collusion with smaller companies in order to come down on their competitors. This tactic is novel because it allows the smaller companies to do the "dirty work" and engage competitors in lengthy and expensive trials. In the case discussed, Rockstar is an independent company that allows companies like Microsoft and Apple to engage in patent litigation through a sort of "proxy".
http://arstechnica.com/tech-policy/2013/10/patent-war-goes-nuclear-microsoft-apple-owned-rockstar-sues-google/