How to pronounce "persona"

where people are interacting with others,

they're commenting, they're sharing,

they're not just reading.

So Facebook is not the only place you can do this,

but it's the biggest,

and it serves to illustrate the numbers.

Facebook has 1.2 billion users per month.

So half the Earth's Internet population

is using Facebook.

They are a site, along with others,

that has allowed people to create an online persona

with very little technical skill,

and people responded by putting huge amounts

of personal data online.

So the result is that we have behavioral,

preference, demographic data

for hundreds of millions of people,

which is unprecedented in history.

And as a computer scientist, what this means is that

I've been able to build models

that can predict all sorts of hidden attributes