It might sound obvious, but search engine spiders won’t find content and links that you’ve hidden away. Your entire site should be structured so that no web page gets left behind.
The folks over at SEOmoz have a great article on Internal Link Best Practices that clearly lays out how you can structure your site so that pages don’t get orphaned. Their main point is that links from the home page should be kept to a minimum so that the spiders can hit as many pages as possible as they travel through your site.
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