“Buying a banner, you have no control whether ten different people see your ad on…” — Gil Penchina

Focus. It's powerful to do just one thing and pour all your energy into it.

A mistake I've made is investing in my idea rather than the entrepreneur's. Sometimes I'm excited about an idea that is similar to the entrepreneur's idea - but not the same. A smart entrepreneur will convince me it is the same, until I write a check!

There are lot of ways people get non-economic payback - learning, networking, and relationships. These drive most angels more than the money.

I was one of the early folks at eBay, and by 1999, it was completely overrun by consultants from McKinsey, Bain, and BCG. It went from being a cool, fun startup to an MBA factory.