The only user information that are stored are: username, e-mail and password hash
The only information about PORTVL pieces that are stored are: picture, url, description and construction state
You can delete your account at any time in user settings section. All user information (username, e-mail and password hash) will be deleted. However, the user PORTVL pieces will remain. PORTVL pieces owner will be set to "anonymous".
Private information are not, and never will be, sold