Zendesk officials said the company was hacked by an unknown attacker and that emails belonging to users of Twitter, Pinterest and Tumblr all were accessed.
If you have a Twitter, Tumblr and Pinterest - Change your password.

""Our ongoing investigation indicates that the hacker had access to the support information that three of our customers store on our system. We believe that the hacker downloaded email addresses of users who contacted those three customers for support, as well as support email subject lines. We notified our affected customers immediately and are working with them to assist in their response," Mikkel Svane, the Zendesk CEO, wrote in the blog post. "
 Zendesk Compromised, Twitter, Tumblr and Pinterest Users Affected | threatpost