Plugins are something new that you are going to find on your dashboard while moving to self hosted wordpress blog. Plugins, as the name suggests, adds more features and addons to your blog.
Most Popular Plugins:
WordPress.com stats â€“ so that you wonâ€™t miss your stats as you used ton wordpress.com blogs. This plugin needs a wordpress.com API code, which you fill find on your wordpress dashboard ( link )
All in One SEO â€“ For SEO crazy bloggers. I have installed it, but not sure how to make the best out of it. Yep, I am not a SEO guy.
Auto Tager : Suggests and adds tags automatically when you write, edit and publish your blog posts. Very useful.