The Ping-O-Matic plugin sends a ping http://pingomatic.com/ after you publish a post. Ping-O-Matic is a service that updates different search engines letting them know that your blog has been updated.
GM Code or GMcode stands for GreyMatter code. It provides style formatting without HTML tags.
The Generic ping plugin can be used to add a generic RPC ping service to your blog.
This plugin adds a widget that can display either or both Facebook Like and Share buttons. The widget can also show how many users have already liked and shared the current page.