Pinterest, which CEO Ben Silbermann describes as a tool that helps people find inspiration, is now the third-largest source of referral traffic on the Internet.

But growth wasn’t easy for the company, Silbermann told a rapt audience at Y Combinator’s Startup School at Stanford University on Saturday.

The way Pinterest grew had little to do with Silicon Valley wisdom. It was about marketing — mostly grassroots marketing — not better algorithms.Pinterest CEO Says Growth Was Through Marketing, Not Engineering [allthingsd.com]