This is great! Perfect timing too. I've been using postmark for over a year, and have recently been looking to other providers for an inbound service.... soooo glad they did this!
That is a personal question. However, here are two books that might help you answer it: (1) The Black Swan and (2) Early Exits: Exit Strategies for Entrepreneurs and Angel Investors (But Maybe Not Venture Capitalists)
It is important that a startup understands the technology they are working with. But, it is equally important that they understand the cultural context of that technology. This video does a good job at addressing the anthropologically side of web 2.0.