I meet Ezra at RailsConf 2007, this was pre Engine yard if I am not mistaken. At this point he was all merb. He was fun to be around, very positive attitude and extremely smart.
When I was very new to Rails, I heard a talk Ezra gave at a RailsConf about the work he had done setting up and configuring servers for EY when they were just starting out. He spoke about the technical details with great enthusiasm for a few minutes and then stopped, laughed, and said "Can you tell I love my job?".
Merb started as essentially a wrapper on top of mongrel handler. Merb = Mongrel + erb. Mongrel had concurrency and it was super lightweight. However, it did not have goodies like routing or templating engine. Ezra write Merb as modular framework which did not care if you used datamapper or active record. Haml or ERB.
Sad day…