Looking for some information, I happened to come across this listing of the top fifteen web sites for learning jazz piano:
I have no idea how these ratings are derived, but I thought it was interesting that PianoGroove came in number 7–ahead of Berklee (from the famed Berklee College of Music) and OpenStudio.
Well done guys! 
I’ve seen some of these websites before and even tried to work with one or two. I just took a quick look at the others. Totally unimpressed.
I don’t know how these ratings are derived either; but none of the other websites even begins to rival PianoGroove for professionally produced, well-constructed lessons at all levels, not to mention timely answers to theory questions, this community bulletin board, the live seminars and classes. Hands down PianoGroove is #1.