Thousands of Twitter users were tricked into thinking Jack Black had died, thanks to a sick prank by one of the hackers.
It's not clear if all the celebrity account hacks are related, but the sheer number is unusual. Facebook CEO Mark Zuckerberg also had his LinkedIn and Pinterest accounts compromised, and the hackers claimed they obtained his password from the recently leaked LinkedIn password dump. It's likely that Zuckerberg reused the same password on multiple sites, a big web security mistake.
Recent reports have suggested that hackers are sharing a 2012 leaked password dump from LinkedIn much more widely. LinkedIn responded recently by resetting passwords impacted by the hack, but if you haven't changed your LinkedIn password recently then now would be a good time. If you're in the password changing mood, now is also a good time to ensure you're not using the same password across multiple sites.