While giving a presentation on legal research on the Web earlier this week, one of the presenters showed me this new legal search engine -- PreCYdent. It contains free access to federal and state case law and continues to accumulate older case law. The webpage explains:
PreCYdent search technology ranks results by 'authority', using mathematical techniques, such as eigenvector centrality, similar to those used by advanced Web search engines, as well as proprietary techniques we have developed that are specialized to the legal domain. PreCYdent search technology is able to mine the information latent in the 'Web of Law', the network of citations among legal authorities. This means it is also able to retrieve legally relevant authorities, even if the search terms do not actually occur or occur frequently in the retrieved document."