I keep seeing a figure of 56% market share for Moodle. 56% of what? and where is this information from?
Background information:
I am in an LEA which wants us all to use DigitalBrian - see www.digitalbrain.com or www.kick-a-dead-whale-up-a-beach.com 
We have adopted Moodle (Y9 - Y13) and have also encouraged our feeder schools (middle schools Y6-Y8) to do the same. We're looking to Shibboleth authentication across the pyramid.