If you want to use Facebook, but don't want Facebook's tendrils extending all over the internet and following your account, you'll want this. Facebook Disconnect completely blocks the social network's ability to track your account around the web.
Like buttons, share buttons, Facebook comment threads, Facebook logins—all these now-ubiquitous adornments will be nuked entirely. So you'll lose some functionality, but if you're a privacy maven, you'll have the peace of mind that Mark Zuckerberg can't know anything about you after you close the Facebook.com tab. [Facebook Disconnect]