The Web (in general) and Google (in particular) spent the better part of this decade wreaking havoc on the newspaper, which previously had mono- or duo-polies in their local (respective) markets. The next decade may be spent doing the same to a highly-profitable niche: legal publishing.
Legal research is dominated by two companies: WestLaw and Lexis-Nexis.
Judicial opinions are public documents. But by publishing a vast swath of judicial opinions (and assigning them "official" book and page numbers, West established a defacto monopoly over the way cases are referred to, as codified in the standard reference. West also summarized cases by subject matter, in a system called "Headnotes."
(As an example, Smith v. Jones(*), 5 F.3d 123 means that the opinion in the case of Smith v. Jones can be found beginning on the 123rd page of the 5 volume of the "F.3d" series of case reporters. But "F.3d" is a series of books published by West, and in order to find the case, you need to either refer to the physical book or sign on to WestLaw. Contrast with a Bible cite, like John 3:16, which refers you to the 16th verse in the 3rd chapter of the book of John, but which is independent of any particular Bible publisher.)
Lexis-Nexis developed its own system of citation (independent of West's bound books), and the two companies have essentially shared a duopoly over computerized legal research since the 1970s.
So Monday's rather understated announcement on Google's blog that Google will make legal cases available (without charge) on its Google Scholar site has potential long-lasting implications. West and Lexis will need to find ways to compete, and it is unlikely that their margins will remain unaffected for very long.
URL citations have been creeping into legal briefs and opinions over the past few years; Google is betting that that trend will continue.
And with AdWords alongside them?