Technically this is possible with Google Analytics using the "GA for Flash"
tracking code and AS3.

The way it works is you do all of your tracking within a "hidden" or 1x1 flash
SWF object hosted on a central server. Since all of the flash "cookies" are
stored against that SWF, it acts just like a 3rd-party cookie, and can track
across domains.

Though, just like 3rd-party cookies, there are plenty of privacy concerns to go
along with it too.

--- In webanalytics@yahoogroups.com, Kara Womack <kara.womack@...> wrote:
>
> Does anyone know of an analytics solution that is capable of tracking
> and measuring unique visitors across a network of sites without
> relying on 3rd party cookies?
>
> (Apologies for the repost and for the cryptic subject of my initial message)
>
> Thanks,
> Kara
>