What David Sacks looks for:
1. Product Hook- something easy for people to engage with product.  Simple behavior that people will do (interaction)
E.g. in case of Yammer: "What are you working on?"
2. Solving market problem. Some need in the abstract.
3. Distribution model. Vitality for example.
4. Non copy-ability. Network effect for example.

What Marc Andreessen looks for:
Huge market
Differentiating technology
Incredible people 90%
- courage (determined to not stop)
- genius

What Mark Cuban looks for:
- the company’s core competency
- why you’re great
- how the idea is protectable
- how the business can scale