Virtual Midi is just Midi data but it allows you to control one app from another within the same device without any Midi cables etc. So you can control Sampletank from Cubasis or play Thumbjam from Geo Synth for example. I understand that Ik is working on adding Audiobus to the Sampletank app, that will probably be the first. My view is that we are rapidly reaching the stage that any serious music app is going to have to have Audiobus before people will even consider getting it. No AB, No Sale!