Brandon Moeller

This plugin allows publishers to better control the width of photos that use the WordPress caption shortcode feature, when that content is displayed in RSS feed readers like Google Reader, as displayed on small-screen mobile devices.
This plugin accomplishes the same thing that adjusting the “function img_caption_shortcode” code in includes/media.php would, but allows the user to automatically update WordPress without worrying about losing these changes.
It is the author’s hope that in future releases of WordPress (post 3.3), this plugin will prove unnecessary if (hard-working, responsive-minded) WordPress core developers decide to include the fix in newer versions of the awesome great open source software we have all come to love.
The code for this plugin was inspired by code found on this page of the codex: 
<a href="https://codex.wordpress.org/Function_Reference/add_filter" rel="nofollow ugc">https://codex.wordpress.org/Function_Reference/add_filter</a>
Read more about RSS Responsive Caption on the author’s website here: 
<a href="http://brandonmoeller.com/blog/2011/12/18/rss-responsive-caption/" rel="nofollow ugc">http://brandonmoeller.com/blog/2011/12/18/rss-responsive-caption/</a>

RSS Responsive Caption

Improves WordPress caption elements so captioned images in RSS feeds responsively adjust to fit within Google Reader’s screen on Android devices.

padraic

Implements <a href="http://pubsubhubbub.googlecode.com/svn/trunk/pubsubhubbub-core-0.1.html" title="the PubSubHubbub protocol" rel="nofollow ugc">the Pubsubhubbub protocol</a> based on the current PubSubHubbub Core 0.1 Specification and any changes since its publication. <a href="http://code.google.com/p/pubsubhubbub/" title="PubSubHubbub" rel="nofollow ugc">PubSubHubbub</a> is an open, simple web-scale pubsub (publish/subscribe) protocol capable of notifying one or more Hub Servers (e.g. the reference open source <a href="http://pubsubhubbub.appspot.com/" title="implementation on Google App Engine" rel="nofollow ugc">implementation on Google App Engine</a>) of your blog updates so they may be forwarded to any of your feed’s Pubsubhubbub enabled Subscribers as quickly as possible.
Any Pubsubhubbub enabled Subscriber can then receive an almost immediate update from any of your Hubs containing the actual update for immediate use. Subscribers know what Hubs to use when subscribing to your RSS 0.92, RDF/RSS 1.0, RSS 2.0, or Atom 1.0 feeds since this plugin will insert one or more links to your configured Hubs into these feeds.
WP Pubsubhubbub has the following features:
<ul>
<li>Supports multiple Hubs configured from the settings page</li>
<li>Pings all Hubs whenever you publish/edit a blog post</li>
<li>Adds suitable Atom namespaced link elements for each configured Hub to the top of your RSS 0.92, RDF/RSS 1.0, RSS 2.0, or Atom 1.0 feeds</li>
<li>Maintains compliance with the Pubsubhubbub 0.1 Core Specification and any outstanding amendments</li>
<li>WP Pubsubhubbub utilises a Pubsubhubbub Publisher implementation which is fully unit tested for reliability and specification conformance, based on Zend Framework’s upcoming Pubsubhubbub component for which I am the lead developer.</li>
<li>Where no replacement Hubs are configured, WP Pubsubhubbub defaults to the reference Hub hosted on Google App Engine. This is a very reliable Hub. We also default to using the Superfeedr Hub as an alternative to ensure reliable service. You may replace or add to this list as needed.</li>
<li>Version 1.1.0 also enables Hub notification of changes to your RSS 2.0 Comment Feeds</li>
</ul>
As the specification authors state on the main Pubsubhubbub site, the protocol is decentralized and free. No company is at the center controlling it. Anybody can run a hub, or anybody can ping (publish) or subscribe using open hubs.

WP Pubsubhubbub

Implements a Pubsubhubbub Real Time Publisher informing Planet Earth of your updates now, not later!

RSS Responsive Caption vs WP Pubsubhubbub