Migrating a site to a new platform or domain, or implementing a major redesign, is one of the most stressful situations in search engine optimization. The potential for massively impacting organic search traffic and sales is higher during these launches than at any other time. But with planning and priority on the SEO impact of the launch, it’s possible to actually improve SEO performance after a major launch event.
However, most sites neglect to include an SEO professional in the planning, design, development and launch phases of the project, typically resulting in a loss of SEO performance post-launch. While an experienced SEO professional can certainly come in afterwards to guide the team through a strategy to revive the site’s SEO performance, this process typically takes three to six months of planning, rework from the design and development teams, and a loss of traffic and revenue in the interim.
Speaking from experience helping clients through many platform changes, redesigns, domain moves and other assorted SEO pitfalls, these are my best tips for arriving at the other end of the launch with your search engine rankings safely intact.
Migrations on the Same Domain
Most migrations occur on the same domain, where a site needs to implement a new ecommerce platform perhaps, or is redesigning the site for better branding and usability. Even if the subdomain, domain and top-level domain ("TLD," such as .com) don’t change, the URIs are likely to change in these situations. And anytime a URI changes there will be an impact on SEO.
URIs are the name by which search engines know your pages. It’s how they’re stored in the engines’ indices. Changing those names without warning or helping the engines understand how the new URIs relate to the old URIs they have indexed is like starting all over again with fresh pages that have no history or link popularity. That’s essentially SEO suicide.
The first step is to bring in an SEO professional at the start of the project. Until the wireframe redesign stage, it’s unlikely that the SEO will do much more than absorb information, but that background can be invaluable when it comes time to actually making recommendations. The SEO professional should be involved all the way through design, development, pre-launch testing and post-launch monitoring.
URLs and Migrations on the Same Domain
Whenever possible, keep the URLs the same. In a cosmetic redesign, where the same pages are getting new skins, this should be entirely possible. In a more complex redesign or a platform migration, URIs are likely to change. When there’s a one-to-one match between pages, make every effort to use URL rewrites to convert the new URI to the same old URI that the engines know and love for that page. For example, if a site has a sweater category page before and after the redesign or migration, and the purpose of that page will remain relatively constant, then the platform’s new URL of http://www.jillsclothingsite.com/sweater-x147gh?cid=43 should be able to be rewritten to the pre-migration URL of http://www.jillsclothingsite.com/sweaters/. Even if URL rewrites are only done for the most important pages of the site – those that drive significant organic search traffic and sales and the major category pages – it’s better than changing every URI on the site. Protect the majority of your organic search traffic and sales by keeping the same URIs for the pages that drive the most organic search traffic and sales.
If the URIs have to change, 301 redirects are the best bet to preserve as much of the site’s link popularity and transfer it to the new URIs. This transfer is critical to not only infuse the new URIs with link popularity and to communicate to the search engines that the URI that they have indexed has moved and should be de-indexed and replaced with this new URI. If you’re unable to use 301 redirects for some very important reason, use cross-domain canonical tags — explained here in Google Webmaster Tools. It’s important to note that canonical tags are suggestions to the search engines while 301 redirects are commands, so be certain that 301 redirects are truly not a viable option before settling for canonical tags.
Some marketers try to play it safe by running the old and new sites simultaneously to ensure that users don’t encounter broken links from various marketing channels. Sites that do this must apply 301 redirects to the old URIs, or the old and new sites will be considered full-site copies of each other and could face duplicate content issues. At the very least, the engines will serve a confused mixture of the old and new URLs to searchers, throwing off the site’s ability to measure the success of the transition to the new site. At worst, the site could drop out of rankings entirely because the new site will be indexed based on internal links but the old orphaned site will have the benefit of the external links its pages have earned over the years. So a few of the strongest old pages may still rank, but the new pages won’t have the benefit of any external links to help them rank and drive traffic and sales.
Navigation and Migrations on the Same Domain
Oftentimes a new design rejiggers the navigation, adding or removing categories and subcategories, merging or splitting categories and subcategories, adding or removing rollovers or other features. Check the URI implications of any navigation change very carefully. Copy all of the URLs in the header navigation and all the URLs in the side navigation and compare the list with the URLs produced on the development site for the header and side navigation. If there’s a large degree of change, expect a similarly large degree of risk to the SEO performance of the site. Push to keep the same URI or at lease do 301 redirects to preserve as much link popularity and trust as possible.
Once the SEO professional can get access to the development or testing environment, he or she will want to identify how many URIs are changing site-wide and whether new sources of duplicate content are being generated. The easiest way to do this is to crawl the site — see "8 Reasons to Crawl Your Clients' Sites," my previous article on that topic. Filtering and sorting in particular tend to generate unwanted pockets of duplicate content, as do some implementations of breadcrumb navigation. Crawling the site and sorting the list of resulting URLs alphabetically will show where multiples of the same base URI are duplicated with parameters of subdirectories to enable these features.
A simple canonical tag referring back to the default URI will resolve any of these sources of duplicate content. In this case, a 301 redirect is undesirable because the URIs have to exist, — i.e., not redirect back to the base URI — for human usability. For example, placing a 301 redirect on a URI that sorts the products on a category page so that products are shown by price would result in the user simply ending up on the default sweater page again without the sorting order they requested. That would be terrible usability. Because the canonical tag affects only search engine crawlers, it’s a safe alternative to canonicalizing in instances where customers need to see the page but it’s redundant to search engines. Make sure to identify and resolve duplicate content issues before the site launches, however, because once the horses are out of the barn — the duplicate content is live and indexed — it’s a lot harder to get them back in that de-indexation barn.