HL Twitter stores tweets from multiple accounts and displays them via widget, archives and shortcodes as well as auto-tweeting new posts.
Twitter button plus is nice and useful tool to show Twitter tweet button on your website.
Evergreen Post Tweeter enables you to schedule and automatically tweet out links to old posts.
The Triberr plugin sends your WordPress posts to your Triberr stream automatically to encourage sharing by tribemates. Get your articles into the Trib
Get more social traffic by easily connecting your WordPress to Buffer, and automatically sharing posts & pages to Twitter, Facebook, LinkedIn, etc
Plugin that automatically tweets your old posts (including custom posts) which helps you increase the traffic on your website.
This plugin allows site owners to automatically schedule and reshare their content on Twitter and increase social traffic without lifting a finger.
This WP Twitter plugin auto posts updates from your blog to twitter, auto shorten URLs with TLI.TL url shortener
Share&Get it ! automatically provides you with either Facebook fans or Twitter followers in return for downloadable content
Automatically tweets each new blog post directly to twitter. Get Top backlinks, inform your followers in real time, all on autopilot.
Tweet2Download allows a wordpress blog to require a tweet and a follow in exchange for the downloads or article parts available on the blog.
feedHi 4WP allows you connect your blog to your social media, for publishing automatically your news and join themed broadcast groups.
plugin for setup Twitter Follow button to every post on your wordpress blog.