Share Buttons for WordPress.com
Install AddToAny in WordPress.com
Enter your WordPress.com domain:
.wordpress.com
then click "Create Share Button" to save AddToAny.
Note: If you do not see "Create Share Button" — click the "Add a new service" link in the Available Services section.
WordPress.com Business
WordPress.com users on the Business plan should install AddToAny's full-featured share plugin for WordPress.com.