It's mainly social media. I built for social media rather than search. I really don't spend that much time on social media - maybe 5% of my work time? The other 95% goes to working on the sites themselves.
My sites are actually not indirectly independent on Google. They were early on, but once you get an established base of regular visitors who network through social media sites, all Google can take from you is their directly referred traffic.
I do realize this approach doesn't work for every site. I deliberately chose niches and topics that had a potential to go viral among growing web demographics. That's not an option if your website is the online expansion of a brick-n-mortar business that sells bedpans.