February 13, 2013 — FORTUNE — The Open Invention Network, a community set up by an IBM-led consortium in 2005 to foster a safe patent environment for developers and users of the free, open-source software operating system Linux, now has more than 500 signatories, the group announced today. The group surpassed that symbolic milestone last December, according to its CEO Keith Bergelt, and now signs up a new company roughly every three days.