I use Skype for both trainig and coaching, and I really like it. Honestly, I only have one client with whom I Skype train and I only offer her this service because we worked together for over a year before I left her city and I know she is capable of completeling the exercises without injuring herself. She just likes having me there to tell her what exercises to do and I what order.
Coaching is mostly talking anyway, so Skype, phone and email are fine for that.
There is some really useful information in this thread! I’m glad i clicked through.