Apple's patent lawsuit against Motorola is just another thread in a rather complicated litigation web, but it's also unique for busting out multi-touch, a hallmark feature of modern smartphones.
In total, Apple is wielding six patents across two lawsuits against Motorola, as detailed on Patently Apple. The lawsuit is a counter-attack against Motorola, which in October claimed that Apple infringes upon 20 of its patents, so 26 patents are actually in play.
But the two patents that raised my non-lawyer eyebrows are the following:
Ellipse Fitting for Multi-Touch Surfaces: "Apparatus and methods are disclosed for simultaneously tracking multiple finger and palm contacts as hands approach, touch, and slide across a proximity-sensing, multi-touch surface. Identification and classification of intuitive hand configurations and motions enables unprecedented integration of typing, resting, pointing, scrolling, 3D manipulation, and handwriting into a versatile, ergonomic computer input device."
Multipoint Touchscreen: "A touch panel having a transparent capacitive sensing medium configured to detect multiple touches or near touches that occur at the same time and at distinct locations in the plane of the touch panel and to produce distinct signals representative of the location of the touches on the plane of the touch panel for each of the multiple touches is disclosed."
You don't have to be a master of legal jargon to see that both patents involve touching a screen with multiple fingers at the same time. Apple has never used these patents for lawsuits before, and from what I can tell, Apple's lawsuits against other smartphone manufacturers, such as HTC and Nokia, don't specifically target multi-touch.
The closest Apple has come in the past is with "Touch screen device, method, and graphical user interface for determining commands by applying heuristics," applied against both HTC and Nokia. This was once regarded as Apple's key multi-touch patent, but as Engadget's Nilay Patel points out in January 2009, there's really nothing multi-touch about it. The patent simply covers the way an iPhone can tell if you want to scroll up and down only, or side-to-side as well, based on the angle your finger hits the screen.
This seems kind of crazy now, but there was a time when other smartphones didn't use multi-touch. After Palm broke the mold with the Pre, and didn't get sued, Android followed, and multi-touch is now a standard smartphone feature. According to one rumor, Google had a gentleman's agreement with Apple not to use multi-touch in Android, as part of a fragile partnership between the two companies. Apple and Google are now bitter smartphone rivals, so the agreement has presumably fallen apart.
Apple won't attack Google directly in court, so for now Motorola's taking the blame for allegedly using one of the iPhone's most important features. The implications would appear to be huge, but as with all the other patent lawsuits in play, this one's not going to be resolved anytime soon.