The leader of Silicon Valley's hottest startup factory: Don't focus on growth before product

Startups in Silicon Valley are expected to grow everything, and fast. Venture capitalists expect to see hockey-stick shaped charts, and often founders will try to "hack" growth to deliver that insane speed of growth investors expect.

That obsession with growth may have gone too far though, warns Y Combinator president Sam Altman.

"We tell startups all the time that they have to grow quickly. That's true, and very good advice, but I think the current fashion of Silicon Valley startups has taken this to an unhealthy extreme-startups have a weekly growth goal before they really have any strong idea about what they want to build," Altman wrote in a blog post.

By focusing on growth and growth hacking, they're skipping over the step of making sure they are building something great.

Founders should wait until users love a product so much they spontaneously tell others to use it, Altman says. Once they've hit that metric, then it's time to grow the team and the company, but not before.

"The very best technology companies sometimes take awhile to figure out exactly what they're doing, but when they do, they usually pass that binary test before turning all their energy to growth. It's the critical ingredient for companies that do really well, and if you don't figure it out, no amount of growth hacking will make you into a great company," Altman wrote.