Inside Social lets you require social actions: facebook likes or twitter follows, from site visitors to access specified site content.
Plugin for interactive sharing on all your pages and posts on Google Plus
Browse and select photos from any public or private Google+ album and add them to your posts/pages.
Plugin/Widget for Social Media Icons
This plugin enhances the WordPress comments by incorporating Twitter and Social Bookmarking systems(Hatena, Delicious, FriendFeed, livedoor clip, Buzz
Follow & Subscribe siderbar widget adds links to your Facebook, Google Plus, Twitter, linkedIn, Pinterest, Xing, StumbleUpon, YouTube, About.me, f
Enables the well-known "Share this" buttons for different social networks, but with respect toward's your user privacy and data.
This plugin will add social share icons for the 4 major networks to the bottom of WordPress posts.
Datenschutzfreundliche Social-Media-Einbindung (Facebook, Twitter und Google+)
KN Social Slide is a free WordPress Plugin that lets your visitors know about your facebook, twitter, google+, feedburner and random entry!
Add Google+ Direct Connect Badge & allow your WordPress/BuddyPress users to register or login via their Google+ account & import their stream
Google+ for Wordprsss shows you lastest posts.