It's not only Apple and Samsung who are busy suing each other and additional tech companies. According to a report, 40% of patent infringement cases filed in 2011 were filed by trolls.
These patent trolls don't develop the technology themselves; these non-practicing entities or patent assertion entities (to use some more official terms) just buy up patents with a view to making money from companies that often unwittingly infringe on the patents. It's a little like a game of monopoly except the patent trolls aren't even in the hotel business.
According to the study into the "Effects of Patent Monetization Entities on US Litigation", lawsuits filed by patent monetizers have increased from 22% of the cases filed five years ago (2007) to almost 40% of the cases filed in the most recent year (2011).
The study showed that patent monetizers were unlikely to advance very far in the trial process, generally settling prior to a summary judgment decision.
Back in June a study from the Boston University School of Law found that patent litigation caused by these non-practicing entities, or patent trolls, cost US software and hardware companies £19 billion (US$29 billion) in 2011.
Patent litigation has become standard business practice in the tech world, and no rivalry demonstrates that better than Apple and Samsung.