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.

If you can use a Web browser, you can use Skype.

Surround yourself with smart, dedicated people - to build something isn't a one-man show. It's more important to have smart people who really believe in what you're doing than really experienced people who may not share your dream.

I try not to dwell on big mistakes but to move on when I make a mistake. I make mistakes most of the times and that's part of the risk profile being an entrepreneur. I guess one big mistake I did was not to start my own company earlier. I spent nine years working for others before starting Kazaa in 2000.

They also can combine voice with instant messaging and online file sharing.

Today as an entrepreneur you have more options.

The telephone is a 100-year-old technology. It's time for a change. Charging for phone calls is something you did last century.