Two years after a widely publicized study in which they identified the risks of Web sites silently installing persistent Flash cookies on users' machines, a group of researchers has done a follow-up study that found not only are some of the same sites still re-spawning Flash cookies, but many other sites are using new technologies such as HTML5 to store cookies and at least one was using cache cookies to uniquely identify users even when they've disabled cookies and are in a private browsing session.