The good news for wordpress.com blogger is that there is now a convenient method to verify ownership of their blogs with the 3 big search engines.
The method is for Google Webmaster and Bing Webmaster Center verification. The easy to follow step by step instructions can be found in the WordPress.com Support Documentation at the Webmaster Tools link.
Bloggers with wordpress.com blogs cannot not verify ownership by adding the meta tag or file as we all work on a wpMU (multiuser) blogging platform and cannot access and edit the underlying templates for our blogs. Consequently, in the past the method we used for verification was the alternate method.
We offer two methods of verification. You can either upload an HTML file with a name that we specify or you can add a meta tag to your site’s index file. — Google
This amounted to creating a new Page and giving it the title which was the code for verification and then deleting or making the page private once verification was achieved.
Related posts found in this blog:
How to: Google Site Verification
Google Changes to Meta Tag and HTML File Verification Methods