The Ping-O-Matic plugin pings http://pingomatic.com/, from where your ping gets relayed to a set of most common ping services.
Category: "Other Plugins"
Adds a toolbar on top of the post editor for easy HTML tag inserting.
The source code of this plugin is not available
The Transport optimizer plugin helps you saving bandwidth.
It supports ETag headers and GZip compression.
The Generic ping plugin can be used to add a generic RPC ping service to your blog.