Browser configuration capture?

I recall seeing (a couple years ago, at least) a site that would capture info about a visitor's browser capabilities and configuration and and email it to whomever they wished. I believe it even had the ability to automatically do so if the admin created the link with their email address passed as a parameter, but for the life of me, I can't remember what the site was. It was cross-platform and cross-browser compatible.

Does anyone remember this?