Google has just unveiled a system to display laws, case rulings and citations. Modelled after much of the work at the various LIIs around the world, this system helps make american legal opinion much more accessible. From Google,
We think this addition to Google Scholar will empower the average citizen by helping everyone learn more about the laws that govern us all. To understand how an opinion has influenced other decisions, you can explore citing and related cases using the Cited by and Related articles links on search result pages. As you read an opinion, you can follow citations to the opinions to which it refers. You can also see how individual cases have been quoted or discussed in other opinions and in articles from law journals.
See for example, the citations for the famous Roe v. Wade case. Very happy to see this technology come for american laws as there is no US equivalent to our amazing CanLii.