* Yes, please create a starter feed for me of popular content.
* No, I want to start with a blank feed so that I can gradually add things on my own.
That way there's both an explanation of why all those strangers are listed, and a mechanism to curate more carefully.
Facebook was bootstrapped off existing IRL social networks (i.e. Harvard undergrads)
As for word-of-mouth spread at Harvard about Facebook, well that's not different than anything else. Word of mouth is always a part of marketing for any product. You still needed to manually look up your friends or your friend's friends and even to see what was up you'd have to visit their profile (until the feed came out later). Facebook didn't start off by showing you thousands of people you didn't care about, it did the opposite, it wanted you to connect with people you knew IRL.
Some will say, "well, why not Zuck?" Well, androids still have that uncanny valley effect and they're not quite as relatable.
Which is the point.