Every number links to its source. Blank means no source publishes it.
How your credit appears on the site, what you know, and which emails you get.
Shown as "Contributed by" beside values you added. Your email is never shown.
Categories you know well. It helps moderators, and it is where we will ask for help first.
Sign-in links are always emailed. Everything is also listed under Notifications.
The account pages need JavaScript.