It's getting so that data breaches aren't news anymore unless they're huge. The Gizmodo article calls it The Mother of All Breaches, exposing 773 million email addresses and 21 million passwords. There's a more complete post by Troy Hunt: The 773 Million Record "Collection #1" Data Breach. Hunt is the person behind the Have I Been Pwned website. That should be your next stop -- it lets you check to see which of your email addresses, usernames, and passwords have appeared in any data breach.
If your password shows up in Pwned Passwords, stop using it. Consider enabling two-factor authentication where you can, and getting a password vault. Hunt recommends 1Password. If you want open source, you can try KeePassX.