Social networks such as Facebook should be focussing on connecting people based on the places they go as well as the people they know, says university researchers.

Three researchers at the Cambridge University Computer Laboratory said that while traditionally social networkers have used the 'friend-of-a-friend' approach to suggest others web users should connect with, the massive numbers of users of these sites has meant this approach is not as effective as it could be.

"While millions of users may represent good news from a business perspective, it means the task of recommending friends can become an exponentially difficult one, if, as in the case of Facebook, you have 750 million active users," said one of the researchers, Salvatore Scellato.

However, following a four-month study that looked at how how users of location-based social network Gowalla created connections, Scellato believes social networks should recommend new friends based on the places where users 'check-in'.

"We discovered that about 30 percent of all new social links appear among users that check-in to the same places. Thus, these 'place friends' represent disconnected users becoming direct connections," he said.

"By combining place friends with friends-of-friends, we can make the prediction space about 15 times smaller and yet, cover 66 per cent of new social ties."

Scellato said the properties of the places we interact can determine how likely we are to develop social ties.

"It turns out that offices, gyms and schools are more likely to aid development rather than other places such as football stadiums or airports. In those places, it's highly unlikely people will develop a social connection," he said.

"Our results show it's possible to improve the performance of link prediction systems on location-based services that can be employed to keep the users of social networks interested and engaged with that particular website."