Intellectual Ventures was founded by Nathan Myhrvold (former CTO of Microsoft) and Edward Jung back in 2000. In addition to a small number of things developed in its own laboratory, the company has reportedly hoarded over 30000 patents. It is important to note that the few things it did develop on its own have not been superficial - for instance, they've been awarded with the MIT Technology Review Top 10 Emerging Technologies in 2009 for a safer nuclear reactor design.
Both Samsung and HTC have signed a deal with Intellectual Ventures, giving both of them access to this massive patent pool. Obviously, Samsung and HTC also hand over their patent portfolios to Intellectual Ventures, allowing them to manage them. A pretty decent pool of patents to defend themselves with against patent aggressors like Apple and Oracle, I'd say.
"HTC is one of the fastest growing companies in the mobile phone industry, and it understands the value of actively protecting its invention rights," said Peter Detkin, founder and vice chairman at Intellectual Ventures, "Given HTC's innovativeness in developing some of the industry's first smartphones and its continued development of some of the world's most advanced products, HTC is forward-thinking with its IP practices and is working with IV to mitigate its IP risk."
While I understand HTC joining hands with Intellectual Ventures (HTC is relatively young), I'm not entirely sure why Samsung would need to sign such a deal. Samsung is huge, and supplies all sorts of chips and components to just about everyone in the business, so it would seem Samsung is pretty safe from patent lawsuits. Of course, it could be that Samsung and HTC are actively working together on this, and are simply using Intellectual Ventures as an intermediary.
Samsung has not yet been involved in any patent suits, but obviously, any suits against Android hurt Samsung's mobile phone business as well. While I loath the kind of patent hoarding Intellectual Ventures does, I can sympathise with both Samsung and HTC taking defensive action against patent aggressors like Microsoft, Apple, and Oracle.