Your site will have taken many regenerations and have had many pages added over the years of it being live. If you have been pro-active, you will have written regular blog content in order for Google to rank ongoing activity and relevance. But when transport content onto a new site or new server it is likely you pick and choose which content to transfer over….don’t!
Deep linking is a key part of a back linking strategy, and back linking is a pivotal part of an SEO presence. Google and other search engines rank your page on a number of factors, but one of them is how many links each individual page receives from relevant sources. If you are getting numerous links back to your page from influential online locations then that page is going to rank higher in search engines results. But Google also ranks links back to a page from other pages from the same site.
This is why navigation plays such a key part in your web design from an SEO perspective, but also why old blogs and previous content should not simply be deleted, but archived instead. Search engine results are often a numbers game, with Google judging how important a page is by the number of links back to them (as long as they are from relevant sources and not ‘spam’). So keep old blog posts and make sure they link to other pages on your site….Google will thank you for it!