In your profile there is a Hide Communities list that lets you configure which communities show up on your profile page. The list displays all the sites you have an account on. It presents their names and it's alphabetically sorted... except it's sorted by URL, not by name. This means while most sites appear to follow alphabetical order, some are missing from where you'd expect and instead appear in surprising locations.
- Arqade doesn't appear among the A's where you'd expect to find it. Instead it's at the beginning of the G's, because its URL is
- Stack Overflow en Español is among the E's because its URL is
- Cross Validated is among the S's because its URL is