HTML e-mail is the most popular method to format e-mail messages, and uses HTML. While most e-mail clients support HTML e-mail, the level of support is even more diverse than among web browsers. The situation gets even more complicated by web-based e-mail clients like Gmail and Hotmail, where first the HTML e-mail source is transformed into an HTML snippet that is inserted into the HTML source of the e-mail client, and secondly the web browser (or other user agent) renders the HTML page.