First, thank you for your knowledgable answer. You helped a lot.
So, is it safe to say that Bitcoin is first technology ever to use PoW for consensus making? Is that the most important innovation of Satoshi?
The major innovation by Bitcoin was the use of blocks to form a timestamping mechanism to (partially*) solve the byzantine general problem.
Didn't hashcash solve byzantine problem by usage of timestamping? I think I read something about that.
dzoni