In the right sidebar, click the "Privacy Settings" tab
Scroll down to the bottom of the page and click the "delete your account" link in the paragraph of text.
You'll be asked to confirm that you do, in fact, want to delete your account (Note: there is no undo), and once you click the big blue button, your account and check-in history will be deleted completely from our system.
If you delete your account, it will be gone from our system. There is no way to un-delete an account.