Contextual search within Wikipedia:
We are excited to announce that we've built a Custom Search Wikipedia skin that makes it easier for you to complete your research on Wikipedia. Wikipedia allows users to register and personalize their Wikipedia environment via the configuration of options and the use of styles or skins. Just log in to Wikipedia, enable the Custom Search skin and you'll have quick access to relevant Google Custom Search results from Wikipedia. With the Custom Search skin, your search results are conveniently placed inline on the page. After you've reviewed the results, you can dismiss them and return to the current article of interest without having to switch to a different tab on your browser; you can access the relevant Wikipedia articles right within the Wikipedia interface.
The Custom Search skin also features contextual search — searching across different sets of pages as you navigate Wikipedia. For Wikipedia pages with a lot of information and links, contextual search lets you limit your search to only those Wikipedia pages that are linked from the current article, focusing the results on the topic of the article. So, in addition to getting all matching Wikipedia articles, you can quickly drill down to contextually relevant results using the Linked Wikipedia Pages tab.