No. Third party cookies do something similar, but don't always work with all browsers/privacy settings. Specifically, Safari won't accept third party cookies fr

No. Third party cookies do something similar, but don't always work with all browsers/privacy settings. Specifically, Safari won't accept third party cookies from non-blessed domains (one the user didn't navigate to on purpose). Some IE flavors needed the cookie to have a compact privacy policy in the header, something that was never audited or checked...total honor system. This was a big problem at my last job, trying to get an accurate count of unique visitors to a network of around 50 distinct domains. Nothing nefarious, just trying to get a sense of which visitors on site A were the same (anonymous) visitors on site B. Flash "cookies" work with more desktop browsers, although they always felt like an ugly hack.