We are all familiar with the real world impact of "presence" - and the powerful clues to social context that it provides...

Ok, ok, some examples.

Do you think twice about entering an empty restaurant surrounded by thriving atmospheric venues?

Do you feel a lift in adrenalin at one of the world's great sporting venues filled to capacity with screaming fans? (I was lucky enough to be at the Melbourne Cricket Ground in 2005 for the mighty Swans victory...).

On the other hand, have you read about the great European soccer clubs who have had to play matches in stadiums without fans able to attend - due to previous fan behaviour? Can you imagine the (lack of) atmospherics and adrenalin in an empty stadium?

You may also be aware of how just the act of observation can influence behaviour - the so-called Hawthorne effect observed in controlled studies. Or at a more intense level of scrutiny or adulation, the commonly referred to "fishbowl" effect. Think Michael Jackson (apologies) or Hollywood starlets...

So if these are real and quite powerful phenomena in the real world - how does this all relate to our experience online particularly in online communities?

Clay Shirky describes the decision to join an online community in the following manner...

Any new claim on your time must promise something of value - and presumably some higher value than something you already do... But it is not a promise alone. You must not only assess that it will be of value to you but "will enough other people feel as I do to make it take off?" Shirky calls this the "plausible promise".

And once you have joined such a site you will be looking to assure yourself that this is indeed a healthy and active site worthy of your time.

This, of course, is the same power of presence we recognise in the real world just adjusted to the foibles of the online environment. Just remember, that "on the internet, nobody knows you are a dog..."

And it is a similar phenomenon to the power of recognition, reputation and embeddedness mentioned by Tim that can ultimately develop in online communities. But it has to start somewhere, and just knowing that "somebody is home", that "there is a pulse" provides a very powerful and necessary context.

So, to continue our line of inquiry... have you been to social websites where...

You can immediately see a number of recent member generated comments...? (thebuzzexchange, everydaymatters)

The number of registered members or members currently online is displayed? (essentialbaby)

Have you been to a "social" website that measures contributions, has leader boards or recognition badges? (digitalministry) Did this perhaps lift your adrenlin levels and competitive spirit just a smidgeon...

My case rests, your honour.