For years, BlackBerry-builder Research In Motion (NASDAQ:RIMM) has endured lawsuits brought by technology holding company NTP over patents on wireless email delivery methods. In March 2005, RIM finally settled with NTP for $450 million. The settlement ended litigation (or so RIM thought), removed uncertainty, and revived investors' enthusiasm. RIM's stock jumped more than $12, or 18.5%, on the day of the announcement.

Since the settlement, however, the U.S. Patent and Trademark Office has struck down crucial NTP patents left and right, invalidating four of the five principal patents in the lawsuits. After reviewing the patents, the USPTO has determined that it should not have issued them at all in their current form. Investors are now debating whether RIM will even have to pay up on the previous settlement. (Even before the recent patent invalidations, RIM and NTP seemed to have different understandings of the terms of their settlement agreement.)

The companies' ongoing patent battle matters to investors for a number of reasons. Obviously, litigation saps millions from RIM's bottom line. But the twists and turns in this debate also resonate with larger issues in intellectual property rights: its role in the marketplace and the current proposals to reform the patent system.

The decision on the patents' validity isn't final. NTP will have a chance to contest the action; some experts believe this process may let NTP strengthen its patents. The courts don't necessarily have to reconsider cases due to the patent invalidations, either. The recent invalidations may actually bolster NTP's position.

In addition, licenses obtained for the contested patents from industry players such as Good Technology and Nokia (NYSE:NOK) gives NTP some form of validity by consensus. Even if these companies may just have agreed to license the patents to avoid costly litigation, their deals make it harder for RIM to argue that NTP's inventions are hollow and sidestep the settlement. Whenever the end finally comes, NTP will still likely collect a juicy portion from Research In Motion's licensing.

Fool contributor Dave Mock thinks wireless email is the greatest thing since sliced bread, and whoever thought of sliced bread should have patented it. He holds no financial position in companies mentioned here.