A time capsule blog post that documents three search tools that were beyond Google in their focus in 2007: A9, Krugle, and CiteSeer.
Beyond Google: A9, Citeseer, and Krugle
I had lamented that I always Google too late, but lately I’ve been getting better. Here are some tools to use beyond Google and LinkedIn for searching for different kinds of specialized information.
A9 [Discontinued, see Wikipedia A9.com ] let’s you search the contents of any books that Amazon carries, all of Amazon, and another 500+ specialized information sources.
- Update 2026: A9 pioneered a number of novel search capabilities and had development efforts in areas of product search, cloud search, visual search, augmented reality, advertising technology and community question answering. It was never able to break away from Google and was ultimately folded back into Amazon.
Citeseer [Discontinued, see Wikipedia CiteSeerX] which seems to me to be more useful than Google Scholar, searches scientific and academic papers.
- Update 2026: See Wikipedia’s list of Preprint Repositories that now complement Google Scholar, with the most famous preprint currently active is ArXiv (www.arxiv.org)
Krugle [transformed several times, see Wikipedia Krugle and https://www.krugle.co.jp/en/about/], searches code examples and some related technical references.
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- Update 2026: Krugle has been largely replaced by modern enterprise and open-source code search engines like Sourcegraph, built-in GitHub Code Search, and SearchCode, which handle massive multi-repository indexing, regular expressions, and AI-assisted code comprehension.