If you use an iOS device, chances are you've used Apple's iCloud to back up your data at some point. And as the service grows, Apple is telling some users that they're close to hitting their 5GB "free" threshold. Unfortunately, it appears that plenty of people have no idea what iCloud is. Buzzfeed has collected tweets from people who are being urged to upgrade their storage space on a service they've never heard of.

Obviously, there are always going to be people who aren't familiar with a given service, and it doesn't necessarily tell you anything about them or the tool. Some tweets may also be facetious, though these don't seem to be. But iCloud backup is a major part of a ubiquitous operating system, even if it's not something many users interact with the same way they would Dropbox. If Apple wants to sell people on upgrading their accounts, it may need to make iCloud more accessible first.