Would you open the front door of your home to a stranger? Would you share your day-to-day life with them, beyond Facebook status updates and tweets, to learn more about culture, language and social interaction?

We are constantly engaging with our connections on social media sites, but how many of us actually make a difference to someone’s life? How many of our friends do we socialise with offline? How do our offline relationships stack up against our online ones?

Has virtual engagement replaced real-life community?

Social scientists claim that, ever since Neolithic times, human brains have been hard-wired to cope with a maximum of approximately 150 friendships at any one time. It’s probably evolved from the ages when we lived in small tribal units, yet this number is still reflected in today’s real-world lives.

But what about virtual relationships?

Research shows 150 is also the optimal amount of ‘inner-circle’ virtual friends. So, whether we are interacting in person or online, the number is the same.

CouchSurfing is a social networking site that builds a bridge between real-and virtual-world connections. The premise is simple: you get in touch with people living in a city to which you’re travelling and arrange to meet up for a coffee, an event, or even to sleep on their couches and share their lives. In the process, you expand your social network, build real-time relationships and make new friends.

The brainchild of San Francisco boy Casey Fenton in 1999, this international travel-oriented network now spans 240 countries and 330 languages, connecting like-minded people around the world. CouchSurfing allows us to respond to diversity with curiosity, appreciation and respect; it’s created a global community.

The difference between CouchSurfing and most other social networks is in its sense of offline engagement and personal fulfilment. Does this suggest a move towards online social communities forming real-life friendships?

Indisputably, virtual engagement has changed the way we communicate on a day to day basis. However, rather than stifling face-to-face interaction it might cultivate tangible relationships in our offline global network.

But not more than 150, of course.