What is the best WordPress Plugin for Affiliate Marketing?

Pretty Links is a WordPress plugin that can help you unlock more affiliate revenue from your existing content. Pretty Links allows you to manage your affiliate links manually or automatically. Through Pretty Links' automation you can save time by letting the plugin insert the correct affiliate links based on keywords. With Pretty Links its also easy to cloak your affiliate links, serving them with the URL of your liking using the Affiliate Link Cloaker.

ThirstyAffiliates is an affiliate link cloaking and redirect plugin for WordPress. However, ThirstyAffiliates is more than just you run of the mill affiliate link cloaker, its a tool designed to help you as a blogger to make more money. It includes tools for auto-linking keywords, creating reports with charts and tables for actionable statistics, geo-location linking, smart uncloaking, proactive link fixer that ensures that your affiliate links are always up to date, automatic 404 checker and integration with Google Analytics events.

Lasso is a WordPress plugin designed for affiliate marketing. With Lasso you can improve the revenue earned per visitor. Lasso provides plenty of tools, including Custom Link Displays, Affiliate Opportunities Dashboard, Affiliate Dashboard,  Amazon Integration, Link Cloaking, Link Groups, Click Tracking, and Link Alerts. All featured in a neat UI that is intuetive and easy to use.