There are a number of things that you can learn, though as with many SEO questions, the answers are not necessarily definitive. For example:

1) The order of the pages that are displayed may be indicative of how much authority each page has
2) You can see how many pages are indexed in Yahoo

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Portland Real Estate | Portland MLS | Eugene Real Estate
Milan Cole, Real Estate Broker
JMA Properties LLC, Portland, Oregon
(503) 953-3416