Acer has been making waves the past few years, and have in the past few years entered the top tier of notebook providers. That success may come at a cost, however, as they are being taken to court by HP, who claims that Acer is violating several patents owned by them. The laundry list is large, including patents related to many common features of just about any notebook series:

HP believes Acer infringed on patents ranging from DVD editing, power management, processing capabilities, clock switching, and other technologies from 1997 to 2003. HP wants both unspecified damages and an injunction forcing Acer to immediately stop selling some products on the U.S. market.
I doubt that HP will be able to prevent Acer from continuing to sell, but it's entirely possible Acer may end up paying out the nose. Their high growth the past few years poses a distant, but looming threat to the HP, who is nearly neck and neck with Dell for the #1 spot in laptop sales.