Must-Have WordPress Plugins - AddThis Social Bookmarking Widget

AddThis allows your visitors to easily bookmark or share your posts with a variety of social websites, by email and even allows them to easily print. You can also view stats about what your visitors share with a free AddThis account.

Website: http://www.AddThis.com

With the AddThis plugin, you can add social bookmarking/sharing options, choosing from a variety of looks and positions on your WordPress blog. AddThis code can also be inserted to any HTML page, so is very versatile.

A few examples of how the widget can look:

There is also a library of custom icons made by 3rd party designers. You just have to check the terms of use before you use them on your site. Some peeks at custom work:

AddThis also comes with in-depth stats that shows you shares over a time period you specify:

You can also view your most popular posts (private details blocked)…

…and the most popular services that people share to.

Other stats include audience profile, top keywords and countries.