Chris Evans, the Storage Architect, had an interesting post last week about how two airports in Europe were closed recently because a couple WWII bombs were found. He then goes on to discuss data storage "time bombs", one of the biggest threats to archived data.
I've thought that archiving services are the best option for most businesses. Why do this yourself if you don't have to? I would rather not be responsible for the details if there are others who are going to specialize in it. Security and privacy concerns have to be addressed as do redundancy and survivability.