in which zombie cookies may be hidden include: Standard HTTP cookies Storing cookies in and reading out web history Storing cookies in HTTP ETags Internet Explorer userData storage (starting IE9, userData is no longer supported) HTML5 Session Storage HTML5 Local Storage HTML5 Global Storage HTML5 Database Storage via SQLite Storing cookies in RGB values of auto-generated, force-cached PNGs using HTML5 Canvas tag to read pixels (cookies) back out Local shared objects (Flash cookies) Silverlight Isolated Storage Cookie syncing scripts that function as a cache cookie and respawn the MUID cookie TCP Fast Open TLS's Session ID If a user is not able to remove the cookie from every one of these data stores then the cookie will be recreated to all of these stores on the next visit to the site that uses that particular cookie. Every company has their own implementation of zombie cookies and those are kept proprietary. An open-source implementation of zombie cookies, called Evercookie, is available. Controversies In 2015, TURN, an online advertising clearinghouse, introduced zombie cookies based on Flash Local Shared objects. Privacy advocates quickly denounced the technology. An academic study of zombie cookies was completed in 2009, by a team of researchers at UC Berkeley, where they noticed that cookies which had been deleted, kept coming back, over and over again. They cited this as a serious privacy breach. Since most users are barely aware of the storage methods used, it's unlikely that users will ever delete them all. From the Berkeley report: "few websites disclose their use of Flash in privacy policies, and many companies using Flash are privacy certified by TRUSTe." Ringleader Digital made an effort to keep a persistent user ID even when the user deleted cookies and their HTML5 databases. The only way to opt-out of the tracking, was to use the company's opt-out link, which gives no confirmation. This resulted in a lawsuit against Ringleader Digital. The term "zombie cookie" was created by Attorney Joseph H. Malley who initiated the Super-Cookie Class Actions in 2010. The etiology of the phrase was derived from his prior research into Apple's third-party iPhone applications. Some of these which had been criticized as being "zombie-like" applications such as the "super-cookies" which "re-spawned" when deleted. Attorney Malley envisioned a cookie that seemed to come back from the "dead". Blending the two ideas, he first coined the phrase Zombie Cookies within his filed Class Actions,