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I agree 100% with your answer, checking  where most of your backlinks are coming from is very important and changing them to your new website shouldn't be a problem; as well as do look at the deep links and redirect them to the new website as well.

I would like for my website to get more ranckings and more traffic.

Hello,

I believe when you add Yahoo Store to an existing website is actually not  a bad idea, and as far as I know it doesn't affect the Google keyword ranking, but make sure you include the link to your Yahoo and that whatever you write on that page is current and updated.