I know Google Desktop can search web history from a number of browsers, but it is unclear to me if this history indexes only general browsing data (like page title) or also the actual page content of websites visited?
Google's help entry isn't specific about it either:
Google Desktop indexes web history accessed from Internet Explorer (IE) 6.0 and later, Firefox, and Netscape 7.1 and later
This seems to suggest that Google Desktop indexes whatever the browser indexes. This would mean that web history from Chrome includes the page content, whereas for e.g. Firefox it does not. But I am not sure.