The world, they say, gets smaller every day. We travel more than ever, and almost everyone has a story about bumping into friends, family or colleagues in some faraway place.

Those who spend a lot of time on the road know how lonely it can be, and having an idea of who will be in town during your travels can make a huge difference to your time away.

That's where one new web service, Dopplr.com, wants to make a difference. It's a social network that focuses purely on your travel plans - and those of the people you know - in order to encourage serendipitous meetings.

Sign up and tell Dopplr where you're going and who you know, and you'll be alerted (online or on your mobile) every time somebody you know crosses your path.

And while the site was built by a team of globetrotting world citizens, it's not just for people who rack up millions of air miles – the service works just as well for keeping tabs on friends and family as they scoot around the country.

The most hyper-connected web monkeys will be able to incorporate Dopplr into their other social networks (like Facebook) with ease, and new features are being added all the time as the site grows.

At the moment it's invitation-only, but when it opens up to the world later this year you might just start to hear big things about this little website.