Since I have been digging up old definitions, I thought I would post the definition I came up with for social tools, way back at the dawn of time, in 1999. This was published in the last issue of my electronic newsletter, Message. I then slipped into blogging.
[from Message, August 1999]
A new category of software is emerging, software intended to augment social systems. Not to change the company inadvertently, like email did, when the electronic analog of interoffice mail became something else, grew into something else by changing the way people communicated, and led a change in the structure of the company. No, this generation of software is intentional, designed from the start to guide human behavior into new paths and patterns, to counter prevailing ways of interaction. I call these social tools: software intended to shape culture.