( CNN ) -- Tens of millions of online note-takers found themselves worrying about their security Monday , as questions remained about a weekend hack of Evernote . The online note-taking and archiving service began requiring its 50 million users to reset their passwords Saturday after announcing it was the victim of a security breach , making it the latest tech company in recent weeks to fall victim to hackers . In a blog post , the California-based company said its security team `` has discovered and blocked suspicious activity on the Evernote network that appears to have been a coordinated attempt to access secure areas of the Evernote Service . '' The company said no user content or financial information was accessed . But the hackers were able to access user information , including user names , e-mail addresses and encrypted passwords . Evernote said the encryption coding they use to protect passwords is `` robust , '' but still sent the password warning to users of the service , which is popular among college students and others who rely on taking notes for later use . Sophos Security analyst Graham Cluley said in a blog post that it remains unclear how long the hackers had access to Evernote and how they managed to get in . `` What 's not good news , '' he wrote , `` is that the hackers now have access to the usernames and email addresses of Evernote customers . It is easy to imagine how this information could be abused -- for instance , the hackers could send out spam emails to those users claiming to come from Evernote , and trick them into visiting a malicious website . `` And , of course , it 's another cautionary tale about the risks which can exist with trusting the cloud to look after your personal information . '' Like many services , Evernote stores data on remote servers instead of the user 's computer . This allows them to be accessed from multiple computers and other devices . Evernote warned users of the possibilities Cluley noted . He argued that their message -- warning users not to click phony security e-mails while sending out a security e-mail of their own -- could confuse users . Complicating matters is that the legitimate Evernote e-mail pushes users first to a website with the domain name `` mkt5371 '' before taking them to Evernote itself . Cluley wrote that this is a service Evernote is likely using to track how many of its users changed their passwords and says not to worry . `` That 's a technique commonly used in a normal marketing email communications , but looks very out of place in an email about a security breach which tries to hammer home the point to 'Never click on reset-password requests in emails , '' he said . Last week , customer support tool Zendesk announced it was hacked , with the breach exposing the e-mail addresses of users of three other websites -- Tumblr , Pinterest , and Twitter , all of which use Zendesk . Microsoft , Apple , and Facebook last month said they were the victim of hackers , and Twitter said in January that it , too , was hacked . Reports that surfaced last week suggested that a gang of hackers based in Eastern Europe was behind at least some of the attacks , using a website frequented by developers who use Apple 's mobile operating system to worm their way into companies where they hoped to steal valuable information . Evernote launched in 2008 as a way to archive images , documents , notes and other data online . A version for businesses is available in more than 30 countries . CNN 's Melissa Gray contributed to this report .
Tens of millions changing passwords after Evernote was hacked . Popular note-taking tool says no user content , financial info was accessed . Evernote joins Apple , Microsoft , Twitter , Facebook and others in recent hacks . Comment: