strange querystrings from adwords

does anyone know what these are?

[Scally_Ally]

Hello,
have been checking my tracking anjd have found that all of the incoming traffic from adwords seems to land at a page with a querystring after it.
I have never seen this before. here are a few examples of where they land.

/?gclid=COCQyJDpgZECFQgziQodHk...
/?gclid=CJPygJf3gZECFQJEMAodjC...
/?gclid=CKDL17T9gZECFRvIXgodwS...

Does anyone know what this is?

Thanks
Ally

[smallcompany]

My Account > Account Preferences

Tracking - Auto-tagging: Yes

[google.com...]

[Scally_Ally]

Brilliant, thanks..

I had never seen it before.

Ally

[edited by: Scally_Ally at 2:37 pm (utc) on Jan. 20, 2008]