LOUIS, New Mega Search Gov Docs Database Offers RSS

LOUIS is a new mega search engine of U.S. executive and legislative documents. A project of the Sunlight Foundation, LOUIS offers a combined search of Congressional Reports, Congressional Record, Congressional Hearings, Federal Register, Presidential Documents, Federal Register, GAO Reports, and Congressional Bills & Resolutions. The files themselves come from GPO Access.
Besides the ability to combine sources, another cool thing about LOUIS is the availability of RSS feeds. You can either get an RSS feed of all of the documents from each source, or you can get a customized feed based on your search.

Let’s say, for example, you’re interested in following the congressional hearings regarding the U.S. Attorneys’ controversy. You might go to the Congressional Hearings tab and do a search for the keywords department, justice, attorneys and firing for the last year. In addition to viewing the current results of your search, you can be notified of any future related hearings by clicking on the RSS button at the top and and subscribing to it.
There are some things to be aware of when using LOUIS. According to the LLRX article, The Government Domain: ‘Insanely Useful’ Legislative Sites by Peggy Garvin,

If you are going to use LOUIS as single mass of searchable text, you should understand the coverage of each database first. The helpful explanations available on GPO Access (such as, “most Congressional hearings are published two months to two years after they are held”) are missing from LOUIS. Familiarity with the GPO source files also helps. For example, it is good to know that the hearings database is a database of printed hearings.
In addition, remember that LOUIS is searching and displaying the ASCII text of documents, which often do not have the full contents of the printed documents. In the case of congressional hearings, this can include numerous documents submitted for the record, such as letters and GAO reports. This content is not searchable, but it can be displayed in the PDF version at GPO Access.

There is a five minute video tutorial for LOUIS which I recommend if you are planning to use the site.