Yes, but not easily seen unless you have a tool like FireBug to see.
It works by setting a unique cache tag (etag as in screenshot) for each user of a resource such as HTML, JPG, GIF, etc files. The later requests can then be extrapolated of what the user views per site. It's in effect, a cookie.
I think it's quite brilliant as an alternative to cookies but unfortunately I can't use it as a form of cookies as they are not a HTTP standard.
It works by setting a unique cache tag (etag as in screenshot) for each user of a resource such as HTML, JPG, GIF, etc files. The later requests can then be extrapolated of what the user views per site. It's in effect, a cookie.
I think it's quite brilliant as an alternative to cookies but unfortunately I can't use it as a form of cookies as they are not a HTTP standard.
More: https://secure.wikimedia.org/wikipedia/en/wiki/HTTP_ETag