The bulletin board justification is also ridiculous; GA airports are out of the way and the average person does not make a trip out to see who might be flying where. How could they not have seen this coming?
Flytenow would have been much better served to encourage a more streamlined process for commercial pilots to ride share and navigate any applicable FARs be it part 135 or other. There is certainly an opportunity, not quite on Uber-terms, but there are plenty of pilots with commercial or near commercial doing crappy CFI (instruction) jobs and building time for an airline transport certificate. They will certainly welcome any new revenue or time-building scheme.
The relevant FAR regarding private pilots is here: http://www.ecfr.gov/cgi-bin/retrieveECFR?gp=&r=PART&n=14y2.0...