As an investor, what we're not looking for is 'oh this is a cool app,' it's 'is this something that can become a big business?' You need to find those that can become real businesses.

If you want to be an entrepreneur, it's not a job, it's a lifestyle. It defines you. Forget about vacations, about going home at 6 pm - last thing at night you'll send emails, first thing in the morning you'll read emails, and you'll wake up in the middle of the night. But it's hugely rewarding as you're fulfilling something for yourself.

You shouldn't be afraid of failure - when something fails, you think, 'What did I learn from that experience? I can do better next time.' Then kill that project and move on to the next. Don't get disappointed.

It's extremely hard to build a company with a product that everyone loves, is free and has no business model, and then to innovate a business model. I did that with Kazaa, had half a billion downloads but that wasn't a sustainable business.

When radio stations started playing music the record companies started suing radio stations. They thought now that people could listen to music for free, who would want to buy a record in a record shop? But I think we all agree that radio stations are good stuff.

When we started Skype, if you look at analyst reports, no one forecasted it as a big business. Also when Google started, it was not fashionable to be in search. It's not trying to do the obvious - that's the hard part.

Video is moving online in a big way. It's proven to be a challenging market for some companies that start out as a pure Internet company such as Joost.