At my company, they are cultural principles that make us different from other companies, that bleed into our hiring practice and day-to-day work. For example,

At my company, they are cultural principles that make us different from other companies, that bleed into our hiring practice and day-to-day work. For example, "we are egolessly mission driven" is one of our values: this helps us recruit the right people (drawing people want to work at a mission-oriented company; turning away people who just want a random job), as well as helping us notice and nudge employees who might be (accidentally) engaging in political maneuvering. "we focus ruthlessly on the most important thing" helps us filter recruits out who don't want to take work seriously, helps make our Slack channels much quieter / less spammy than most companies, and helps employees self-improve along the axis of protecting their focus time. Stating explicitly what you care about, and talking about these things a lot, is a huge aspect of how a company defines its culture as it grows beyond ~ 10 people or so.