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Many of the big affiliate and price comparison websites route links through an internal folder first. This allows them to record the conversion, set a cookie, etc... It also makes all of those outbound links look like internal links. Usually it looks somethingl ike this: Web Page hyperlink for "Visit OnlineStore.com" is actually a link to YourDomain.com/partners?merchant=OnlineStore. From there it will redirect (what kind doesn't really matter here) to OnlineStore.com along with any affiliate code you have added to the URL for their tracking purposes, if necessary. Typically /partners is blocked in the Robots.txt file so the search engine can't even follow it to see that it's an external link.