Tuesday, July 31, 2007
When Google originally introduced Supplemental Results in 2003, our main web index had billions of
web pages. The supplemental index made it possible to index even more web pages and, just like
our main web index, make this content available when generating relevant search results for user
queries. This was especially useful for queries that did not return many results from the main
web index, and for these the supplemental index allowed us to query even more web pages. The
fewer constraints we’re able to place on sites we crawl for the supplemental index means that
web pages that are not in the main web index could be included in the supplemental. These are
often pages with lower PageRank or those with more complex URLs. Thus the supplemental index
(Matt blogged about it
and
here’s his talk
about it on video) serves a very important purpose: to index as much of the relevant content that
we crawl as possible.
The changes we make must focus on improving the search experience for our users. Since 2006, we’ve
completely overhauled the system that crawls and indexes supplemental results. The current system
provides deeper and more continuous indexing. Additionally, we are indexing URLs with more
parameters and are continuing to place fewer restrictions on the sites we crawl. As a result,
Supplemental Results are fresher and more comprehensive than ever. We’re also working towards
showing more Supplemental Results by ensuring that every query is able to search the supplemental
index, and expect to roll this out over the course of the summer.
The distinction between the main and the supplemental index is therefore continuing to narrow.
Given all the progress that we’ve been able to make so far, and thinking ahead to future
improvements, we’ve decided to stop labeling these URLs as “Supplemental Results.” Of course, you
will continue to benefit from Google’s supplemental index being deeper and fresher.
Bunu necə tətbiq edirik
We archive Search Central announcements because client questions often trace back to a change that was announced years ago. Reading the original is faster than reconstructing it from second-hand summaries.
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