Now, anyone can search legal opinions, thanks to Google Scholar. Once you click on a case, you can even find some rudimentary "Shepardization" or "Key Cite" under the "How cited" tab. Unfortunately, it is still very basic, so there is no way to tell what kind of treatment the citing work made of it. Nevertheless, if Google can get a team of lawyers to wade through it and index treatments, it would give LexisNexis and West a real run for their money.
By the way, Google, if you're reading this, I'm available for such a project!