A recent issue I was discussing with a client was this: “My company is stopping selling a particular product or technology, but still wants to rank in Google for related searches. How do I make that happen?” For example, you might have sold yellow widgets for years, but now the main thrust is the up-and-coming area of blue widgets, which are making yellow ones obsolete; so much so that you’re taking your yellow widgets off the market.
The main thing to realise here is that no matter how well you’re doing in Google for a specific search, if you remove the page which is doing well, it’ll drop out of the Google results. Redirecting the removed page to the one which supersedes it is of course essential, and will transfer the ‘link equity’ from external links to the old page. However, the content of the new page will be standing on its own two feet, and if it doesn’t mention the products which have been lost, then the pages won’t rank for the related searches. You may have stopped selling yellow widgets, but if you want to continue ranking for searches about them, you’ll need to retain a page about them.
For that reason, if you’re punching above your weight in the search results with a particular search-and-page combination, be very wary about removing that page. If it’s just deprecated technology, why not leave the page on the site, with a message at the top saying that the reader might be more interested in the newer product?