I'm visiting Y Combinator's San Francisco headquarters to talk to two of the people who are integral to Y Combinator — Kat Manalac and Michael Seibel.

Kat is a Partner at Y Combinator and one of the people that convinced us to apply to join the program back in 2014. She's been at YC for five years, focusing on founder outreach, company pitch perfection, and much much more.

Michael is CEO of Y Combinator's accelerator program. He has been through YC himself a couple of times — first in 2007, as co-founder and CEO of Justin.tv — and again in 2012 as co-founder and CEO of Socialcam. Justin.tv later became Twitch and sold to Amazon, and Socialcam was sold to Autodesk.

In this episode we talk about:

* The evolution of Y Combinator. It's changed a ton since Product Hunt went through the program four years ago. They've been working on several programs for founders — things that Michael wishes existed when he went through the program.

* Michael and Kat's advice for founders, including counterintuitive tips they've learned after working with literally *thousands *of startups.

* A key mistake that trips up new founders when pitching their company, as well as advice for founders seeking a technical co-founder.

* How YC has scaled the organization as a 50-person company with its 4,000 (and growing) alumni.

We’ll be back next week so be sure to subscribe wherever you listen to your favorite podcasts. Also, big thanks to our sponsors, Airtable, GE Ventures, Intercom and Stripe for their support.