Facebook 'still expanding' as 500 millionth member signs up

More than 500 million people around the world are now using Facebook to connect with friends, family and colleagues.

The social networking phenomenon started six years ago and saw its 500 millionth member sign up overnight.

The company believes the site is still attracting people overseas and could extend its reach to a billion people soon.

Randi Zuckerberg, sister of co-founder Mark, said Facebook's penetration in countries such as Brazil and India, was fuelling the growth.