Accessibility of Math on the Web, Part II

Unfortunately, much of the material that is available on the web is not accessible in the sense of easily discoverable:

• Virtually all searches are text-based, thus requiring one to know good search terms in advance. Unless you know [X,Y] is called a Lie bracket, finding that out from the 13M hits for "[X,Y]" on Google is hard.
• Because so much of the math that is online is locked up in PDFs, images, etc, text-based searches often fail, or cover only the abstract material.
• What little metadata is available is mostly at the document level and restricted to cataloging info.