Crawls the indexable Web.
Lookup TLDs here: http://www.norid.no/domenenavnbaser/domreg.html
Indexes metadata from scholarly journal articles, technical reports, and other select documents. Also indexes full text of articles to the extent this is possible.
Unlike Google Web, data can be parsed and stored in fields (author, title, date, source) for accuracy in retrieval. See my Research Guide on Google Scholar:
http://libguides.du.edu/content.php?pid=86031
Scholar is strong with publisher content (University of Chicago Press journals; Cambridge journals; Oxford University Press; Blackwell Synergy), but weak with aggregated content (ProQuest Central aggregated titles; EbscoHost Academic Search Premier aggregated titles; Gale Expanded Academic ASAP aggregated titles).
Partners with libraries that use OpenURL resolvers so that contextualized links appear in Scholar records. This is how it works.
Indexes metadata provided by participating libraries, but doesn't seem to be able to leverage that metadata to the extent that Scholar can. Nevertheless, its strength is in full text indexing of texts.
It's strength is that it partners with online publishers and booksellers (such as Amazon.com and Barnes&Noble.com). Even more significantly for librarians, it partners with OCLC's Open WorldCat (http://www.worldcat.org/). Users can start with Google Books, and then be referred to their local academic or public library for the "full text" in print.
Four different views: Full View; Limited Preview; Snippet View; No Preview Available
Some Google Book titles are available through partner projects. For example, Hathi Trust scans are higher quality scans of Google Books.
Title: The Divina commedia of Dante, tr. into English verse by James Ford. Author: Dante Alighieri, 1265-1321. Date: 1870: Hathi Trust | Google Books
Title: La Divina commedia [di Dante Alighieri] riveduta nel testo e commentata da G.A. Scartazzini. Author: Dante Alighieri, 1265-1321. Date: 1903: Hathi Trust | Google Books (can't find it yet)