When you register a username account at WordPress.com the email address you provide becomes your unique identifier. When you are logged into WordPress.com and register a blog it’s registered to that username account and associated email address. You can register as many blogs as you wish and provided you are logged in, all the blogs you register will be registered under that username account and the associated email address.
Deleting a Blog
To delete a WordPress.com blog, go to Tools -> Delete Site in your Dashboard. You will undertake a step by step process wherein three warnings will be issued letting you know the result will be permanently deleting the blog address ie. URL and all content. An email confirmation will be sent with a verification link in it and when you click that link the blog address ie. URL will be deleted forevermore. Note that deleted blog addresses ie. URLs are not recycled at WordPress.com.
Deleting Blog Content
If you decide you no longer want your WordPress.com blog content but do want to retain the blog address ie. the URL, you can easily delete all blog content by yourself.
If your content is a large collection then you can post to the WordPress.com support forum and Staff will delete all the content for you.
Deleting a Username Account
Username accounts are not deleted at WordPress.com. This is what you can do:
1. You can go to My Account-> Edit Profile and remove all data except the account name and an email address. Create a throwaway email address and change the account email to that throwaway address. This only leaves the username behind.
2. To unsubscribe from email sent to you from WordPress.com, go here
and click on “Block all email updates from blogs you’re following on WordPress.com”.
3. To ensure the account is locked up tightly, visit this site, generate a password of 15-20 characters, and change the account password to it:
4. To hide your Gravatar profile, please read “How do I hide my profile?” section of the Gravatar help page.