Don't be alarmed (I'm not trying to fear monger) but I have a good source that has warned that sometime in the next 7 years there is going to be a major outage/attack on the web and that everyone should back up all data they want to keep safe (stuff on your computer/stuff in cloud storage/uploaded to youtube/facebook/ etc and everything else) on devices that are not connected to the web and cannot be remotely accessed (like on external hard drives/USBs etc).

Best to do this now and tell others you know to consider taking these precautions.