It is one way of saying: find way to get traction first and then have bigger vision later.
This is really a long way of saying "deliver a MVP (minimum visible product) ASAP" or "ship early, ship often". Nothing new there.
I didn't read it that way. I think he points out that sometimes you have to come up with a feature that wasn't in your original vision for the product in order to gain initial traction. I think it's a good thing to keep in mind - you don't have to gain traction solely through marketing effort.
no, it's not. it's saying that if you can quickly gain an audience (the hard part) by deliberately making a "feature" that can spread quickly (instead of a full-fledged product) you can parlay that audience into something more substantial later.
(delivering an MVP or shipping early is more oriented towards quickly seeing if a market exists/initial assumptions are correct)