Are BlackBerry users in trouble? They're not involved in the lawsuit. But if the injunction does go into effect, they may lose service inside the U.S. There would probably be exceptions for users in public safety organizations, plus a 30-day grace period.

But while RIM has exhibited a penchant for brinksmanship, it is considered unlikely that RIM will submit to an injunction rather than settle. As noted by Gartner Inc. analyst Martin Reynolds, RIM has 4 million users paying $25 a month -- and no responsible company walks away from $100 million per month in revenue.

What are those infringed patents? Principally, we're talking about good ol' 5,436,960, titled "Electronic mail system with RF communications to mobile processors and method of operation thereof," which was filed May 20, 1991. And then there are four others: 5,625,670, 5,819,172, 6,067,451, and 6,317,592, each with a similar title; they are considered continuations of the first.

What do the patents cover? To quote the trial findings, they describe a system where "a message originating in an electronic mail system may be transmitted not only by wireline but also via RF, in which case it is received by the user and stored on his or her mobile RF receiver. The user can view the message on the RF receiver and, at some later point, connect the RF receiver to a fixed destination processor, i.e., his or her personal desktop computer, and transfer the stored message."

Isn't that too obvious to be patented? A lot of patents seem obvious after the fact, noted Reynolds, adding that it hardly seemed obvious in 1991.