Before you start backing up your files online, it's good to identify the types of files you want to back up. You should make sure your most important files are getting backed up and exclude files you don't want to back up.
Here are the top 4 most backed up file types
If you store these types of files in common places such as My Documents or Desktop, most well known online backup services such as MyPC Backup, Mozy, or Carbonite can back them up automatically without you doing any configuration work.
For most people MyPC Backup is the easiest to set up and the most intuitive to use. We were highly impressed with its ease of use and started recommending it to family and friends. It was so easy that I gave my Dad a web address and in 5 minutes he had it installed and the backup running!