"Look at someone like this guy right here," Alex Taub says, intently peering at his laptop screen.
We're in Taub's office right off Union Square in New York City. It's the headquarters of SocialRank, the startup he co-founded. SocialRank shows companies and public figures with brands to promote which of their followers on Twitter and Instagram are most valuable.
Taub's pulled up his own Twitter account to show me one of his own followers, someone who seems valuable.