Evernote is still trying to fend off an attack that is disrupting its service, according to the notetaking service's service page.
On Wednesday morning, the page stated that Evernote was "actively working to neutralize a denial of service attack," and users may experience problems trying to access the service. Evernote has more than 100 million users.
Distributed denial of service (DDoS) attacks usually involve using many computers (such as those caught up in a botnet to hammer a targeted web service with so many packets of data that the service simply can't cope. To give you an idea of the volume this can involve in extreme cases, a DDoS attack in February ran at over 400 gigabits per second.
In the case of Evernote, details are scarce, though a company spokeswoman told the BBC that the attack began around 2.25pm PT on Tuesday. At the time of writing, that means the attack has been going on for close on 10 and a half hours. Evernote is mostly back up and running, but some users are reportedly having trouble synchronizing their data between devices.
DDoS attacks are unfortunately becoming a standard cost of doing business online. Just in the last few days, similar attacks have also targeted the French music-streaming service Deezer and an unnamed gambling site.