The US Court of Appeals has has decided that in the future, instead of automatically granting a patent for a business practice, there will be a specific testing procedure to determine if that process is truly patentable. The decision is a nearly complete reversal of the State Street Bank decision in 1998, which started the rush to patent business practices.
When you hear the phrase "business practice" patents, think Amazon's "1-Click" process or Priceline.com's "name your own price". There have been questions about the validity of many of these patents, as some of them are clearly obvious or "normal daily procedures".
Certainly, software and service companies (read "Silicon Valley") stand to be hard hit by this change, as it may well invalidate many of their patents and thus decrease the value of their patent portfolio. Open source advocates will be very pleased with this decision.