(from Purdue Owl)
"Titles for Websites, Blogs, and Social Media: The title of a website that is analogous to a traditionally printed work but does not have (and never had) a printed counterpart can be treated like titles of other websites. For example, Wikipedia can be treated as a website, rather than as a conventional encyclopedia. This is a departure from previous editions of CMOS.
Titles of websites should follow headline-style capitalization and are usually set in roman. There are, however, some exceptions: titles of blogs are set in italics and titles of books, journals, television shows, movies, and other types of works should be treated the same whether cited as a print version or an online version. For example, when citing the website of the television news station CNN, the title maintains italics. Furthermore, in cases such as this, when a website does not have a distinctive title, it can be cited based on the entity responsible for the website, for instance, CNN online."