Many of the patents might not hold up in court, but it can easily cost $1 million to mount a defense. For a company whose business model is filing lawsuits, the only incremental cost of each new case is the filing fee - about $500.

With decks stacked like that, most organizations simply surrender, often settling for tens of thousand of dollars.

"It's a shakedown, it's extortion, but it's legal," said Julie Samuels, an attorney who is the Mark Cuban Chair to Eliminate Stupid Patents at the Electronic Frontier Foundation. "It's easy to be a troll, it's cheap to be a troll, and it's totally unethical. It's exploiting a loophole in a broken system."

Labels: development, patents