As soon as you install Skydeck, you have to make an online account which you will then later use to access your account using your computer's browser. As soon as you sync or backup online you can edit you contacts as if you were doing it on your smartphone or Blackberry, since they update each other it makes updating your contacts easy and more comfortable.
You can turn skydeck off to save on data transfer or if you just want to backup on a specific time. Overall I love how Skydeck manages to sync properly with my Blackberry Curve no errors or multiple contacts problems. I find it very easy to manage and make changes in my contacts logging into Skydeck's website.