Time has an interesting article about Google called Google's Growing Grasp. One interesting scoop is that: "Marissa Mayer, who manages search products, says the company has assigned more engineers to search than ever before and plans to release a new search tool that will enable users to design and build their own flavor of Google search, scanning just the sites they're interested in."
This seems related to the new domains recently bought by Google: search-mashups.com, mashsearch.com and other similar domains.
MSN Search (Windows Live Search) already has search macros, that allow you to define a list of sites where you'd like to search (for example, sites about recipes). Rollyo lets you define a list of trusted sources and create your own search engine using results from Yahoo.
So we should expect a similar offering from Google, that will most likely include a way to share your search mashups that combine content from more than one source. Until then you can already do that, albeit not in an elegant way.
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