kithrup

These days, there is another service available that can sorta be used as backups: synchronization services, such as Dropbox, Google Drive, iCloud Drive, and so forth.

These are, technically, not a backup method -- they are, instead, a service to synchronize data across multiple machines. One of the fun aspects of them is that multiple machines means that sometimes different machines will have a different idea of what the files look like, and that results in a conflict. However, you can also use them with just one machine, and lo and behold, you've got a cloud-based backup. Sorta.

Most of these services have been focused on price and features, since there is actual competition. As a result, most of them now offer the ability to look at previous versions of files -- snapshots, in other words.

Most (but not all) of them work by synchronizing local data to the cloud, and then pushing it out to any other connected machines; there used to be a couple that were pseudo-filesystems, in that they would only cache content, and all of the data actually resided in the cloud. However, this tends to work very badly when you are not online. (So good for always-connected machines, pretty bad for laptops you take with you on travel.)

Since these are synchronization services, most of them also support various mobile platforms -- iPhones and iPads, Android phones/tablets, etc.

The biggest downsides to them are:

1. Not technically a backup. They are, however, fairly acceptable for many people's basic needs.
2. Costs tend to skyrocket the more data you have. Apple is generally the most expensive, since they only give 5gb free, and after that you have to pay. Dropbox is $99/year for 2TB.
3. Security can be a big concern. Dropbox, in particular, factors data deduplication into their business model, and this means that your data are not encrypted.