There is literally a plugin for almost anything you want to achieve in WordPress. A quick glance at the WordPress Plugin Directory will show you just how many options are available. Admin, Ajax, Comments, Google, Posts, Sidebar, Twitter, and Widgets are all so very well represented that finding the right one can be a full-time gig. Twitter alone has over 200 plugins dedicated to pulling, pushing, and searching through its masses of data. However, before we can auto-tweet a post, or dynamically interleave links to Amazon products, we have to comprehend how a plugin works, and more importantly, how to install and activate them on our blog.