garo

Everytime you Publish a new post, this plugin will automatically 
send the update information to Pingler.com so the whole world can 
be notified that you keep your content fresh.

Pingler

This Plugin is used to automatically Ping new posts to a variety of online blogs. For use with Pingler.com

ryokurosu

This plugin is to fast index , and optimize ping function. For your website, speed index is very useful way to notify subscribers and users.
This plugin has also ping optimizer. Ping send only publish. 
So tell the world your website is not spam.
This plugin:
<ul>
<li>Sends fast speed notifications when you update your blog</li>
<li>Supports multi-user installations (WordPress MU)</li>
<li>Supports multiple hubs</li>
<li>Supports all of the feed formats used by WordPress, not just ATOM and RSS2</li>
<li>Supports latest specs
<ul>
<li>PubSubHubbub <a href="https://pubsubhubbub.github.io/PubSubHubbub/pubsubhubbub-core-0.4.html" rel="nofollow ugc">Version 0.4</a></li>
<li>WebSub <a href="https://www.w3.org/TR/websub/" rel="nofollow ugc">W3C Version</a></li>
</ul>
</li>
<li>Announces which hubs you are using by adding <code><link rel="hub" ...></code> declarations to your template header and Atom feed</li>
</ul>
This plugin will ping the following hubs:
<ul>
<li><a href="https://pubsubhubbub.appspot.com" title="Demo hub on Google App Engine" rel="nofollow ugc">Demo hub on Google App Engine</a></li>
<li><a href="https://pubsubhubbub.superfeedr.com" title="SuperFeedr" rel="nofollow ugc">SuperFeedr</a></li>
</ul>
Please contact me if you operate a hub that you would like to be included as a default option.

Fast Speed Index

this is a better way to fast index for your website.

Pingler vs Fast Speed Index