rolodex

While it may well be important to have the top 100 influencers on any particular topic following you on Twitter or Facebook, it is not essential. You can make up for it by attracting, retaining, and activating everyone else.
Five and a half decades later, it's a different world -- one that sees, say, a couple billion mobile app downloads per month, and NYC-based Sonar is looking to make its own mark on how people link up.