You can click "unwatch" at the top of the thread, so you will not get emails or other notices when people respond to it.
You can mess with the settings in your account, to turn off all the possible updates and notifications. (Some of them are under "account details.")
You can log out and not come back.
I do not know if there is a way to actually delete your account or not.
If you click "report post," it will let you type a message that goes to a moderator. So if you report your own first post in this thread, you could ask them to delete the thread and your account. (I cannot say whether they would delete them, because I'm not a mod, but that is one way to ask.)