Ever wondered what the most popular free WordPress plugins are and why they’re so freaking popular? Knowing the answer could help you understand which ones are a must to install on your site (or even what kinds of plugins you should be building). The more plugins you include in your site, the more you weigh it down and run the risk of longer pageload times. Instead of overloading your site, choosing your plugins wisely will not only ensure site maintenance is more manageable but can speed up your site.

Source: Top 25 Free WordPress Plugins and Why They’re So Damn Popular – WPMU DEV