In a panel discussion on the potential for digital economy at WEF Annual Meeting, Facebook's COO said there were two brothers in a village in India where they could not go to hospitals, but they joined the technology bandwagon and their lives changed.
"There are many other stories and therefore I am optimistic. Technology is both creator and destroyer of jobs but I am a huge optimist," she said.
Nadella said there was no reason for not being optimistic about what technology can do.
Joining the discussion, Schmidt said there is an enormous revolution taking place.
"...all has been possible for various reasons including because of smart phones. Then the globalisation has made great changes, you cannot isolate yourself anymore," he added.
Colao also said he was absolutely optimistic about the digital economy and he likened it to a movie.
"I can tell you that this is just the beginning of a great story, it is like a movie. We are at the beginning of something amazing. In Turkey, we have farmers who are using our technology and 50 per cent of them are women. Then there is education of teachers in Africa...
"Then there are matured markets where technology is being used for energy savings and a lot many things. The last scene of this movie should be around 10-15 years," he added.
Nadella, however, said the key issue though is that there needs to be a new global consensus that allows technology to progress and yet finds that right balance.
"We need to see the benefit of technology and make sure that this movie gets a happy ending," he added.
Sandberg said she remembers the old Internet joke when a dog before a computer was shown as saying nobody on Internet would know you are a dog.
"Internet was about anonymity earlier but now it gives face to everyone. The power of technology and more so the power of social technology can give people a voice," she added.