“Marketing is too important to be left to the marketing department.”
– David Packard, co-founder, Hewlett-Packard

If you ask 20 business leaders to define marketing, you’ll probably get 20 different answers. Why is marketing so hard to pin down? Probably because most marketers don’t understand it themselves. They spend their careers locked in a narrow purview and never really see the big picture.

Its nebulous nature notwithstanding, marketing plays a pivotal role in business.

According to the father of modern management, Peter Drucker, “Because the purpose of business is to create a customer, the business enterprise has two – and only two – basic functions: marketing and innovation. Marketing is the distinguishing, unique function of the business.”

So, what is marketing? Legendary Silicon Valley venture capitalist and former Intel executive Bill Davidow said, “Marketing must invent complete products and drive them to commanding positions in defensible market segments.” The man should know. He wrote the seminal book on high-tech marketing.

Funny thing is, Davidow didn’t learn marketing in school. All his degrees are in electrical engineering. Steve Jobs, another brilliant marketer, dropped out of school. I’ve run marketing for a number of high-tech companies and my degrees are technical, as well. Not an MBA in the bunch.

So how do great marketers learn about marketing? On the job.

Startup companies are great places to earn your marketing chops because they’re all about developing innovative products and getting customer traction – and not much else. Besides, they’re always strapped for cash and needing people to wear lots of hats. That’s how I got started in marketing more than 20 years ago. Here are 7 truths I learned along the way that every business leader should know:

Marketing is like sex: Everyone thinks they’re good at it. 
There are more posers in marketing than other fields, probably because the demand is strong, the supply is weak, and it’s easy to fake. As David Hornik of August Capital once said, “VCs like to think that they are marketing geniuses. We really do.” The reason, he says, is because “we can fake it far more convincingly than in other areas …” They’re not the only ones.