Gary Illyes from the Google Search Relations team posted another PSA on LinkedIn. This time he said, "when you redesign a site, its rankings in search engines may go nuts."
Yes, this is probably super obvious to most of you reading this site but Gary dives a bit deeper.
He said, "Among other things, search engines use the HTML of your pages to make sense of the content. If for example you break up paragraphs, remove H tags in favor of CSS styling, or add breaking tags (especially true for CJK languages), you change the HTML parsers' output, which in turn may change the site's rankings."
In short, when redesigning, sure - go ahead - make the site pretty. But changing the core HTML can result in ranking changes.
Gary recommends, "try to use semantically similar HTML when you redesign the site and avoid adding tags where you don't actually need them."
So if you can change the design but at the same time keep things in the HTML looking similar, that is your best bet. Change a lot without changing a lot - if that makes sense.
Forum discussion at LinkedIn.
