> Even if Hulu turned off cookie respawning via etags, you can still track users this way, on the server side. I guess the tricky thing is to correlate the etag of the tracker resource with the rest of the requests that a user makes on a site.
The important distinction is that the ETag is literally no different than a cookie, when used this way. Turning off caching is the new turning off cookies.
There is a difference: cookies get sent on requests to any resource in a domain, whereas etags get sent only to specific resources.
> ...the tricky thing is to correlate the etag of the tracker resource with the rest of the requests that a user makes...
Not tricky though. Just put 1-pixel Etagged gif on every page. It gets requested on each page. Or just associate (server-side or client-side) the user's session cookie with the Etag.
Even if Hulu turned off cookie respawning via etags, you can still track users this way, on the server side. I guess the tricky thing is to correlate the etag of the tracker resource with the rest of the requests that a user makes on a site.