After reading this question Is CSS Turing complete? -- which received a few thoughtful, succinct answers -- it made me wonder: Is HTML Turing Complete?
Although the short answer is a definitive Yes or No, please also provide a short description or counter-example to prove whether HTML is or is not Turing Complete (obviously it cannot be both). Information on other versions of HTML may be interesting, but the correct answer should answer this for HTML5.
Answer
By itself (without CSS or JS), HTML (5 or otherwise) cannot possibly be Turing-complete because it is not a machine. Asking whether it is or not is essentially equivalent to asking whether an apple or an orange is Turing complete, or to take a more relevant example, a book.
HTML is not something that "runs". It is a representation. It is a format. It is an information encoding. Not being a machine, it cannot compute anything on its own, at the level of Turing completeness or any other level.