RE: Caterina, it's funny when people write articles saying not to do what they did. I'm sure there were even more compelling post-bubble lists for why people shouldn't start web businesses in Canada, which obviously didn't stop her.
Of course if you always tell people they'll fail, you'll be right 90% of the time, but you'll also miss every single success.
When it comes to your own start-up succeeding, like Mark Cuban says, you only need to be right once.
I totally agree with this. Think about how much it cost to start a business even seven years ago: you had to buy servers and dev tools, etc.
Now you can test an idea for a few thousand dollars and a couple of weeks time by a few people; the market will tell you if it works or not and you're off.
If it doesn't work, who cares-at least you tried and didn't waste too long at it.
Of course if you always tell people they'll fail, you'll be right 90% of the time, but you'll also miss every single success.
When it comes to your own start-up succeeding, like Mark Cuban says, you only need to be right once.