XML sitemap
A machine-readable list of a site's indexable pages, submitted so engines can find them.
What it means for a site you run
A sitemap is the floor, not the ceiling: it helps engines discover pages, especially new or deep ones, but it does not make pages rank and cannot rescue pages a crawler would not index anyway. Every indexable page should be in it — and nothing that should not be indexed.
How Blogotter relates
This site's sitemap is generated from the routes that actually exist at build time, so a page and its sitemap entry can never drift apart.