Necessities for site owners

You have a Backdrop site set up and designed and you've added your content, but what else do you need to consider? Many site owners who create their own sites don't really know that they might need to add other things in order for their sites to be found on the Internet for the appropriate searches, like sitemap.xml, schema.org, etc.

This discussion is intended to be about those technical things a site needs to be "complete," which mostly fall under the category of technical SEO, really includes more than that, like accessibility, etc.

My idea/intention is to have a CMS that can be installed as is and not need a lot of extra things added that are necessary for a site to "integrate" with the Internet, i.e., be found by search engines, integrate as reasonable with other sites/services/etc (mostly, be found, but at least being able to do the others).

This is something that has been on my mind and that I've been thinking & working on for a number of years, but I still really need to nail down the actual description and details of this topic, but maybe this conversation will help with that.