If Google teaches you anything, it's that small ideas can be big.
The companies that I really admire the most are the ones that have a deep visceral understanding of why people use their service, and they figure out ways of making money that are completely consistent with how people are feeling and what they are doing at the time.
There's a lot of pressure to look like the last company that was successful.
Don't take too much advice.
Just build things and find out if they work.