Or just buy patents then sue people?

Considering the two headline categories on their home page are "Litigation Update" and "Technology Aquicistion Program", I'd go with the latter.

Not any more, apparently:

"In 2006, Wi-LAN transitioned its business to focus solely on its greatest asset, the patent portfolio. The key technologies found in the patent portfolio apply to diverse areas of wireless and wireline communications, and have been incorporated into standards by many telecommunications organizations."

of a serious need for the US to totally overhaul its patent system and make software patents invalid.