How to remove your Blogcatalog account
From their site: to delete your account, please e-mail firstname.lastname@example.org with the username and/or e-mail address of the account you wish to delete and a reason for your removal. Deletion requests must be sent from the e-mail address registered with the account you want removed.
Helpful Trick: Removing online data
Helpful Trick: Remove third-party logins
If you signed up for Blogcatalog using a third-party login such as Facebook or Twitter, you probably want to revoke all access from Blogcatalog. Click here to find out how.