At the Getty we use Chicago's 15th edition, which includes some guidance on technical terms, as was mentioned. We are currently in the process of creating a Web style guide, which deals with everything from how to format a link in running text versus in a list, to captions online and writing metadata. Annelisa Stephan is leading that project (astephan at getty.edu).
About the final period after a URL, we use the final period per Chicago in hard copy only - i.e. in printed pieces and downloadable documents online. On Web pages, we advise against presenting the actual URL. Instead, we suggest writing out appropriate text, that is then linked with an href. For example, instead of "For more information about Monet, visit the Metropolitan Museum's Timeline of Art history at http://www.metmuseum.org/toah/splash.htm."; I would write this as "For more information about Monet, visit the <a href="http://www.metmuseum.org/toah/splash.htm";>Metropolitan Museum's Timeline of Art history</a>." Susan Edwards Sr. Writer/Editor, Web Group J. Paul Getty Trust Los Angeles, CA 90049 sedwards at getty.edu 310.440.7510
