Would it be fair to say that the biggest challenge with the buy button is the lack of last mile fulfillment (like shipping, returns etc) from Google/FB/Pinterest. Amazon on the other does a job at this
Developers have a tendency to get overly excited about speed. Fast database, fast search, fast framework, etc. The truth of the matter is that speed should be evaluated within a spectrum. As long as your application latency is within a spectrum, you should be just fine
I'm disagree with his comparison of scala community to "league of legends". I've found the scala community, especially, the #scala IRC to be friendliest so far. Folks are always there to help you out irrespective of your level of proficiency with language or programming in general
In the beginning, VC investment is always potential. Realizing that potential takes time. So, I don't think it makes sense jump to conclusions too soon