How to delete a Wikipedia account?
The description of the service:
Wikipedia is a free online encyclopedia that aims to allow anyone to edit any article and create them. Wikipedia is the largest and most popular general reference work on the Internet and is ranked among the ten most popular websites. Wikipedia is owned by the nonprofit Wikimedia Foundation.
"To delete an account is not possible if you want to leave the project, you can add to your user page and discussion pattern 'Participant left the project and just don't edit Wikipedia pages."