I’m sitting next to a table full of teenagers in Panera Bread, and they are engaging in a form of social networking that you rarely read about these days — hanging out and talking to each other IN PERSON.

What’s also notable is that every one of them has a cellphone in hand. They are constantly showing each other photos and text messages on their phones. The phones are so deeply integrated into their conversation and interaction, they are like extensions of their identities.

I’ve been trying to think back to when I was a teenager (pre-cellphone days) — I don’t know if their was an equivalent to the cellphones as an extension of the teen identity. It seems like an entirely new phenomenon, without precedent.

I’ve been half eavesdropping as I work and haven’t heard a single reference to Facebook or MySpace, nor have I caught a glimpse of Facebook or MySpace logos on their phones.

They are getting up to leave now — perhaps they will all run home and login to their web-based social networking accounts.

But if I were a marketer looking to reach teens, I would be all over the cellphone.

Compare the power of teens sharing relevant marketing messages on their phones with each other IN PERSON to the manufactured social marketing of Facebook Beacon.