The FAA has issued a
second letter concerning riding sharing in response to a question from another such service.
This letter is much more sensible than the Airpooler letter. It's written more clearly and stays away from the 'compensation' question. The FAA lawyers have probably been awakened to the fact that their overly broad interpretation of what constitutes 'compensation' isn't likely to hold up under judicial review.
Mean while Airpooler is
asking some good questions about their FAA opinion letter.
To me Airpooler is pretty clearly 'holding out' because they are selling what amounts to tickets on privately owned airplanes flown by private pilots. The FAA were stupid to bring up 'compensation', since the Airpooler pilots are not compensated by any rational meaning of the word.
I'm glad to hear that question of turning 'letters' in to de facto regulations is being addressed.
In my opinion the FAA ought to do what most other agencies do, which is to charge the questioner for their answer, and limit the scope of the agency's answer to that specific case.
Edited to add:
YES! There exists a pretty good method for amending FAA regulations. It's cumbersome, but it should be cumbersome because there are a lot stakeholders involved.
I don't know the best way to manage or not manage ride sharing web sites, but I do know that having a law clerk write a letter is a very suboptimum solution.