mabujo

googleCards is a google+ wordpress plugin. 
It adds a widget to your blog that will display a link to your google+ profile so people can add you to a circle (follow you). It also displays your name, profile picture and the number of people who have you in circles.
The plugin uses caching to store your google plus profile data to eliminate checking google+ on every page load. 
For the caching to work, your web-server needs to be able to write to wp-content. (a lot of plugins require this so it should be fine). 
If the plugin cannot cache it will still work, but will store the data in the database instead. If caching is working you should see a file called plus_card.txt in /wp-content/cache/. 
As of version 0.4, caching will also failback to using transients to store your scraped google plus data.
Plugin page : <a href="http://plusdevs.com/google-wordpress-plugin/" rel="nofollow ugc">Google plus wordpress plugin @ plusdevs</a>

googleCards

A simple plugin that adds a google+ widget for linking to your google+ profile and showing your number of followers

Christopher Shennan

This plugin displays the twitter posts from a twitter account in the sidebar.
wpTwit is a PHP Twitter Reader based on <a href="http://www.chrisshennan.com/my-projects/linetwit-a-php-twitter-reader-based-on-mytwit/" rel="nofollow ugc">lineTwit</a> which was written for <a href="http://www.line.uk.com" rel="nofollow ugc">Line Digital</a> and based upon <a href="http://www.axllent.org/projects/mytwit" rel="nofollow ugc">myTwit</a> by Ralph Slooten.
wpTwit was written by <a href="http://www.chrisshennan.com" rel="nofollow ugc">Chris Shennan</a>.

wpTwit

Add your twitter posts to your blog using wpTwit - A PHP Twitter Reader based on lineTwit (an extension of myTwit by Ralph Slooten)

googleCards vs wpTwit