In case you missed it, just a day after last month's U.S. Supreme Court decision in Mayo Collaborative Services v. Prometheus Laboratories, Inc., a case with lessons for software patents, the U.S. Patent and Trademark Office issued "preliminary guidance" to patent examiners on how to proceed in light of Mayo. The bottom line: examiners should reject, as not directed to statutory subject matter under 35 U.S.C. § 101, claims directed to laws of nature, natural phenomena, or abstract ideas. Further, examiners should continue to follow the "Interim Bilski Guidance" issued July 27, 2010. Under the latter memorandum, examiners are directed to use the machine-or-transformation test as one tool in determining whether a claim recites a patent-ineligible abstract idea.
The USPTO's Section 101 guidance for examiners speaks for itself, but I am not afraid to state the obvious: after Mayo, as has been the case after Bilski, a lot of claims will continue to fall into a murky grey zone, different examiners will apply different standards for patentable subject matter, and applicants will continue to face unpredictability and uncertainty in the patent examination process.