Domain changes can be worrisome from an SEO perspective. This is only natural as we spend our time building up the strength of particular domains so that they can compete with others. Will Google recognize the old site at the new domain? Will all of the link equity carry over to the new domain?
By considering the problems involved with a change of domain before you execute, it is possible to alleviate many concerns. There is no guarantee that everything will go perfectly, but a little preparation will go a long way to making your transfer as successful as possible.
URL Mapping: Where are we going?
If the change of domain is the only action occurring, then it is likely that a one-to-one redirect, page-to-page, will be sufficient. This may not be the case, though, if the structure of your site will be simultaneously changing with the domain.
If you will be implementing any changes in site navigation resulting in new URLs, or will simply be changing the URL structure on the new site, this issue must be carefully considered. Test all redirect rules on a stage server before committing a domain change to be as confident as possible that there are no 301 loops or 404 errors. Many of the other items in this blog post are potential problems surrounding this one action: messing up the redirect rules is the only method guaranteed to turn your change of domain into a disaster.
And, naturally, make sure these redirects are implemented as permanent redirects (301 status codes) for optimum link juice channeling.
While changing some site elements at the same time as the domain is unavoidable in most cases, be careful about too many simultaneous changes. If things like design or content are changed at the same time as site location, it will become much more difficult, and perhaps impossible, to tell whether any issues with indexation or rankings are caused by a problem with the site move or the other changes that occurred at the same time.
Webmaster Tools: Before, During, After.
Before making any changes, ensure that all applicable domains are verified in Google Webmaster Tools. This includes both www. and bare versions of the domain where possible. It can be painful to have to go back and verify an original domain after redirects are already in place.
During the change (i.e. immediately after redirects have been put in place) submit a change of address in Webmaster Tools. If your domains have been verified, this is quite straightforward.
After the change, be sure to submit your new sitemap to Webmaster Tools if it has not been picked up already by Google. Monitor for crawler errors and indexation. If you desire a more granular assessment of indexation through sitemaps, see Rob Ousbey's post on indexation problems.
Juice passed through redirects decays over time. In order to prevent this where possible, any internal or external links under your control should be change immediately after the redirects to your new domain are implemented. In other cases, you may be able to outreach to other sites linking to your domain in order to get links changed. Prepare a list of sites beforehand for this outreach in order to get this done as quickly as possible.
Another good practice is to have link bait prepared to launch immediately following your move. This will help create an influx of links and social signals to your new domain, hopefully jump-starting crawling and indexation of the new site.
Daily Check Up
After all is said and done, not everything is said and done. A bit of daily monitoring is in order. Some of these things are essentially noted above, but as a checklist of sorts:
- Monitor Webmaster Tools for 4xx/5xx errors.
- Check 301s (i.e. not 302s) and 301 loops. Obviously 301s don't magically change into 302s, but with a lot of changes happening things can fall through the cracks.
- If you have access, monitor crawl rates for old and new domains.
- Monitor indexation via sitemaps in WMT.
- Monitor traffic via Analytics.