There are two ways that you can leave the service: deactivation and deletion. Both options are available via the web or the mobile apps from the account settings screens.
When you deactivate your profile, it is hidden from other users, just as if you had deleted it. Should you decide to log in at a later point in time though, we will restore your profile to it's prior state.
Your profile will be permanently hidden from other users. You will no longer be able to access anything related to the account. You are welcome to create a new profile at a later time, should you so desire.