Notes capitalizes "Web" when used as an abbreviated form of World Wide Web—a proper noun. (CMS16, 7.76, capitulates to the more populist "web" and "website": "In a departure, Chicago now considers web to be generic when used alone or in combination with other generic terms.") It is perhaps noteworthy that, carrying on with recognition of "Web" as a proper noun, are—in addition to Notes—MW11, the Modern Language Association's style manual, the U.S. Government Printing Office, and the New Yorkermagazine (legendary for its fact and style precision).
Title of the Resource
Follow the form established by the producer of the resource as the official title of the product (check the company or organization Web site when in doubt). Do not use the name given by the resource provider (such as FirstSearch, EBSCOhost, etc.) if different:
RILM Abstracts of Music Literature not RILM Music Abstracts (FirstSearch)
Maintain the upper/lower cases, spacing, and any other modifications of normal title format established by the company for its product. Sometimes the form used in the banner of a Web site is not identical with the official version found in the body of the text:
Amazon.com not amazon.com (banner)
Abebooks not abebooks.com (banner)
Barnesandnoble.com not BARNES&NOBLE.com
Follow the capitalization of the site's title as best as can be interpreted.
Roman or Italic?
Grove Music Online
Encyclopedia Britannica Online
Music Manuscripts after 1600 (RISM A/II)
RILM Abstracts of Music Literature
The Music Index Online
Beethoven Bibliography Database
Web of Science
America: History and Life.
Ulrich's Periodical Directory
Books in Print
Melvyl (catalog of the University of California libraries)
Hollis Catalog (Harvard Libraries)
IIMP or International Index of Music Periodicals (we are interpreting this resource as a full-text rather than citation database)
Academic Search Premier
Public Library of Science
Web sites (that are none of the above): use roman, except for exceptional cases when the site has the appearance of a monograph.
Web sites—titles of subpages: use quotation marks.
Library of Congress [main page] > "Arts & Culture" [subpage] > "The Leonard Bernstein Collection" [sub-subpage]
Electronic journals: use italic whether or not there is a print equivalent.
Electronic books: use italic whether or not there is a print equivalent.