- Save Preferences
- Save Location
If selected, these use your browser's local storage mechanism to persist the settings options (style, what to show, etc) and location (what coordinates are centered in the view) for the next time you visit the site. These options are particularly valuable on devices like the iPhone where you can "Add Link to Home Screen", so that if you switch away from the app and back again you won't lose your context.
These days, I find I usually check the options "Filled Borders" and "Dim Unofficial Data" since I want to look for flaws like missing borders or incomplete routes and prioritize corrections, but you may have different options you want to keep.
Anyway - use 'em if you want 'em. Each device you use to access the site will "remember" your settings differently. If you check "Save Location" but want to get back to an overview of Charted Space, click the "Home" button.