Courthouse News Service, a class action lawsuit has been filed against Yahoo for the July hack by the "D33Ds Company" of the Yahoo! contributor service, which allows bloggers to write content for Yahoo! and get paid through advertising. I posted some information on the hack in an article back in July.
New Hampshire resident Jeff Allen is a plaintiff in the case. He found out his information was compromised when the same username and password was used to access his Ebay account. A similar set of circumstances is ongoing with Wired News reporter Mat Honan, when a hacker used social engineering to get Apple support to give him access to Honan's Apple account, and then used that access to pivot and gain access to the rest of Honan's accounts.
Both of these hacks should serve as a reminder to never use the same password on more than one account. One recommendation is to use what is called a "salt" in your passphrase. Pick a phrase that is easy to remember like "I love green hair", change some of the vowels to numbers and add the first three to seven letters of the service you are using. Create a pattern that results in a unique, strong password, and don't store it on your computer.