Magpie now records the time, method, IP address, browser and approximate location of each sign-up and sign-in, on the website and in the app. While you are signed in on the website, it also counts the pages you open in each feature, by day.
Website administrators can see this on each account's page and on a new User analytics page, which also lists accounts that share an IP address. The records are deleted when an account is deleted. The Privacy Policy describes them under Account Activity.