LinkedIn was hacked in 2012, which resulted in 6.5 million passwords being dumped onto a Russian hacker forum. It looks like their entire user database at the time were breached. In my opinion LinkedIn lack of action in letting users know what was truly going on has caused this fiasco. In mid-May, about 117 million members' emails and passwords from the same hack went on sale on a deep web marketplace. Motherboard claims that some of those "no salt" (easy to crack) accounts were hacked within 72 hours, and many of the victims had been using the same passwords since 2012. LinkedIn's poor handling of 2012 data breach comes back to haunt it. If you have a LinkedIn account, for security purposes it is highly recommended to change your password. Read more here ->