I've recently dicovered the "analysis board" , it's really an excellent tool, it allows me to look more moves ahead than usual, play out different options and generally think more clearly about the game. 

My question is this:  is this good for my chess development? Is this helping me to train my mind to think forward? or is this just a crutch that will damage my ability to play in a face to face context, one in which I'm not allowed to fiddle with the pieces b4 I move?

 I'm interested to hear all your thoughts on this.... 

 

I use the analysis board for the very same thing! I usually find a move I'm not too sure about, then try and find alternate moves, looking ahead about 6-7 moves for each. I've found its a very useful tool for learning to look ahead.

I've found it's very useful, maybe too much so! I'm wondering will all the advantages of online chess make it impossible for me to think straight in front of a real board, because honestly, I'm playing online in order to get good enough to play "in the flesh"...

I don't see it so much as a crutch. It allows you to look further ahead then you'd usually be able to. I suppose it's possible that some players could develop a dependency to it, but most people will still play as well, if not better, without it. For my part, it hasn't helped my online games when I don't use it, but I feel that my physical games have improved somewhat.