[GFischer]

Well, AirBnB is a good example of a startup where the real value - and challenge - was in its novel business model, NOT in the engineering challenges of creating their webpage - which is very nice, but they might have succeeded with a Craigslist-like page for all I know if they solved the problem of creating a marketplace.

So I agree with the general idea behind what AngelList is saying. If the startup value proposition is based on solving a "hard " engineering problem, OTOH, it's not such a good idea... but it seems that most problems startups tackle are NOT engineering problems.