Sites like ours that have been around for a decade accumulated rank on pages that have sustained incredible traffic over the years.
As with most sites, our domain was www.marketingtechblog.com.
In recent years, the www has become less prominent on sites… but we kept ours because that subdomain had so much authority with search engines.
Moz has a great breakdown of changes with 301 Redirects that Google has announced which are helping search-centric sites maintain their authority while modifying their site s location.
The two that are key, in my opinion, are:
SSL – Google has encouraged websites going secure and announced there would be no impact in redirecting http to https.