How Will Steemit Scale?

I'm new here and wouldn't say that i understand the fundamentals of how this site runs 100%.

My main concern has to do with scaling.

I was going to check the steemit userbase so i could quote a number and further a point but all i get (and have been getting for 3 days) is a loading circle.

I don't know why this is happening or why it has been prevalent (i'm new) but i'll have to guess it has to do with hosting.

I understand the blockchain is hosted by a voter based system.

What i don't understand is how are the server costs for the actual website steemit.com being paid and can this website ever hope to even handle a userbase as large as facebook's with the same speed?

At some point this website will be handling traffic loads that cost millions a month to maintain, who will contribute all this processing power and upkeep?