A Google Custom Search engine (CSE) is a search engine that anyone can build to search, prioritize, or ignore certain websites. A CSE is often used by a webmaster to create a search engine that searches only the contents of his/her site, but you can also build your own freestanding one, focused on a particular topic. Basically, you can create your own search engine, customized to your own legal research needs.
There are times when it might be helpful to build a CSE that combines many sites with a similar theme. Some examples of a place that have developed its own CSE are New York Law School Law Library and University of Windsor Law Library's Open Access Law Reviews. CALI has also created one that searches law school websites.
Creating a CSE is simple with the help of Google's Custom Search wizard. First, one must log into the Custom Search wizard using a Google account. After filling out some basic information about the search, such as its name and language, you can begin selecting which sites the CSE will search. This is done by typing in the URLs of websites you want into the text box marked "Sites to search:." For example, one would type http://thomas.loc.gov/ into the text-box if you want to add the Library of Congress's website on federal legislation.
Next, the creator has the option to chose a free "standard edition" which requires ads on results pages or a "site search" which yields no ads on results pages for a fee. The creator can then test the search and choose between six pre-made design schemes for the search before completing the creation of the CSE.
While creating a basic CSE is easily accomplished, Google offers information to create a more complex search engine through methods such as using XML to change ranking in the search results or create special results. Likewise, Google offers tools to view, manage, and delete Custom Searches through the My search engines page.
Specificity is a CSE's biggest strength as well as its biggest weakness. CSE gives the control to limit your search to sources you trust, but it removes the factor of serendipity in coming across new sources.