By now, you probably know that you can choose from more than two dozen different online backup services that take your desktop data and make copies of it in “the cloud.” (I maintain a list of many of them here.) They all work in a similar fashion: a small software agent monitors any new files that you create on your PC and it makes copies of them over an encrypted link to the provider’s Internet data center. With so many similar contenders in the field, how do you know which to choose? Here is an article that I wrote for Internet.com that reviews your options.