While the League had stated that only PSK31 and Pactor III are allowed under the new 60 meter regs, a few hams claim that just about any digital mode <=2.8 kHz is allowed. Several have fired up on Contestia and Olivia. A few U.S. stations are using WSPR on 60 now. This can be a mess on a band with only 5 channels and where all digital/CW must be on center-channel.
This morning on 60 I heard what sounded like a QSO between two stations using a mode that was about 2 kHz wide on my Flex panadaptor. It had the shape of a mesa... steep vertical sides and fairly flat on top with one or two "notches" that moved slowly, rising in frequency across the mesa's top.
On 60 there are tons of oddball digital signals from primary users, but what I heard this morning was squarely centered in the ham channel and seemed to be two stations that alternated transmissions of several minutes each. One station was about s-9 and the other s-7. My RSID showed nothing. My FLdigi couldn't print it although I'm hardly a digital pro. Several hams were asking what it was.
BTW, see latest letter from the NTIA on the mind-numbing subject of digital on 60:http://www.eham.net/articles/27993