Google Custom Search Engine

Google has spawned a whole new generation of search engines with the introduction of its Custom Search Engine (CSE). Without any technical knowledge anyone can now use the Google search platform to create a search engine focused on any content they want.

You can choose which pages or sites you want to include in your custom search engine, how the content should be prioritized, whether others can contribute to the index and what the search results page will look like.

Already an increasing number of people are creating niche custom search engines. For example; Specialized Aquarium and Fish Keeping which searches over a hundred aquarium sites, Medical Libraries Blogs which searches all the blogs of medical libraries and librarians or A Dedicated Information Architecture Search Engine.

There is however an interesting anomaly when building a custom search for which I can find no rational explanation. I built a custom search using the seven SEO sites from the SEO Forums post. It would appear that the order of entry of the sites makes a difference to the order of the results. Here are partial screen shots of the tests that confirm this:

Order of selected urls for test 1.Order of selected urls for test 2.


Serps for test 1.Serps for test 2.

The same seven sites in Test Search Engine 1.0 and Test Search Engine 2.0 are searched for the phrase |external nofollow| and produce different results. The only difference in the build was the order of entry of the sites. Other search phrases (but not all) also show similar differences in the order of results.


November 2, 2006

A Google Co-op Engineer has shed light on this test result as follows:

Theres actually a very subtle bug going on here, in one of the search engines an extra whitespace got added to one of the URLs so its actually searching over:

Which effectively renders this URL useless.

Thanks for pointing this out, we’ll fix it in the next release by making sure we do a better job of stripping whitespace off the URLs!

That explains it!

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