It’s a concept that’s been around for many years in varying forms. But unlike the purely online communities most of us are familiar with (chat rooms and bulletin boards), social software is designed to link people in real life.

Perhaps the most obvious application is online dating. Sophisticated software engines look for similarities between people’s profiles to find their perfect match. If the people literally and figuratively “click”, a meeting might follow.

Another example is FriendsReunited.com. It has more than two million members and is now so ubiquitous that journalists and police allegedly use the site for research on celebrities and criminals.

But own my encounter with “social software” began with Ryze.com.

In October 2000, during the dotcom meltdown, San Francisco-based entrepreneur Adrian Scott realised he needed a way of maintaining his network of friends as they quickly changed jobs. Starting as Ryze.org, he simple allowed people to put up their “profile” and also post a list of their friends on the site. Without any sophisticated software it was now possible to start “surfing” the networks of one’s friends and work out the connections between people.

This was a taste of the true “social” aspect of online networking.

As people worked out their geographical relationships, Ryze drinks parties sprung up in most major US cities.

Of course, sites where people “network” online are not new. PlanetAll.com and Sixdegrees.com emerged in the mid 1990s with limited success. PlanetAll was bought by Amazon and Sixdegrees was sold in 1999 – before the crash – for $125 million (