Vladimir Prelovac

WP Digg This is a plugin that adds a Digg button, but with a twist. Instead of adding a Digg button to all your posts, WP Digg This plugin selectively adds the button only to posts you want.
To add a digg button just add a ‘digg’ custom field with value ‘1’.
WP Digg This can display digg button on your single pages but there is an option to show them on home and archive pages as well.
Plugin by <a href="http://www.prelovac.com/vladimir" rel="nofollow ugc">Vladimir Prelovac</a>.
<h3>License</h3>
This file is part of WP Digg This.
Category Search is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
Category Search is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with Category Search. If not, see <a href="http://www.gnu.org/licenses/" rel="nofollow ugc">http://www.gnu.org/licenses/</a>.

WP Digg This

Provides an easy way to selectively add Digg button to your posts. Use 'digg' = '1' custom field in the post to promote it.

preblogging

The best way to increase your traffic from Digg.com and StumbleUpon.com is to get more votes. Often you may have a great blog post, and people do visit via these websites. 
By providing a call to action. This call to action will greatly improve the number of positive votes you will get, and hence in the end you will get more traffic.
<h4>What is new in this version ?</h4>
In Version 1.3, there is the option to specify a your own site. And you can send these visitors a certain message also. Also there is a new test mode !

Increase Sociability

Increase the traffic from social media websites by reminding visitors to vote

WP Digg This vs Increase Sociability