Direct link to delete your account, and of course, all associated Yahoo services cannot be used anymore. So also Flickr (if you have it) will be deleted by this action! If you wish to delete only your Flickr account, find Flickr in our list: you can delete that one separately.
Direct removal link: https://edit.yahoo.com/config/delete_user
If you can't find any contact info and still wish to ask something, for example a question about what exactly is deleted, about data retention, etc., you may contact the domain owners using this info.