What is social about social software?

Before we forget all about the label Social Software and move on to Web 2.0, 3.0, or whatever comes next, I think it would be useful to dwell a little bit on the use of the word ‘social’ as applied in this term. What does it mean for software to be social? Intuitively, we know that Social Software is software that fulfills some sort of social function, allowing us to form social connections, and perform social activities that give shape to social groups. But as evidenced by the number of times I just used the word ‘social’ to define Social Software, it is clear that what we have here is a tautology: by taking for granted what we understand by ‘social,’ the adjective in question both provides an absolute definition and at the same time manages to define nothing.