I apologize that I am late to this thread. I just found it while researching off site storage.
I wanted to add information about a service that might or might not be of interest.
There is an offsite storage service that is kind of a hybrid. It can store deleted files forever. It also automatically backs up new or changed files at an interval you choose.
The service is called CrashPlan. I use it, but have mixed feelings, as outlined below.
Why I Subscribed:
I came out of the Windows environment and was used to crashed files. I also live & work where a local backup drive might more subject to theft than in some other areas. So, I wanted off site storage. It also had to grab only new or changed files. Keeping deleted files was a nice bonus.
It was the only off site I found that let me choose to keep deleted files and automatically backed up only changed or new files. (You can un-keep deleted files by deselecting them from your backup list. They disappear forever.)
What I Like:
1) It uploads reasonably fast. For your first, giant backup you can (for a fee) have them send you a drive to put your files on & mail back. I did not do this, so I can't comment.
2) I can set it to backup changed & new files at any frequency I wish. (I use 15 minutes so when I nuke a CAD drawing, I can get a 15 minute old version.) It saves versions forever, but after a month it will only save one version per day (or some similar time frame- I can't remember.)
3) They have never lost a file of mine from their server.
4) Files are automatically encrypted before being sent, while in storage & while being restored. They de-crypt automatically upon arrival.
5) If you backup a file, folder or disk image with your own encryption, your encryption remains intact when you restore it.
6) Tech Support is usually fast to reply to inquiries. (Usually) Their replies are useful & address the question.
7) If you want to pause it, Pause is 2 clicks away (If the menu bar icon is enabled) But, all RAM is not released. See number 4, in the next section.
8) It is easy to use Terminal to stop the CrashPlan engine completely & release all RAM. (Or you can use their app)
9) If they update something, they let you know it is available by e-mail & how to install the update.
They are very good about updates not messing with your preferences & existing backups.
10) If you need to do something unusual, they will explain how to do it. (Example: Swapping hard drives or computers & having the old computer's data ether be mixed in with the new or appear separately on the Restore list.)
11) It is very, very customizeable. (Is that a word?)
12) If I am at another computer, like a friend's house, I can go to CrashPlan's web site, sign in & download a file without installing anything on their computer other than the file I just 'restored'. All OS's are OK- Windows, Linux, etc. (This I like a lot)
What I Do Not Like:
1) The interface for setting options & restoring files is just plain awful.
The intention is good & well organized, but it just does not work well. If they could make it work, the layout is great.
An example:
The list of files to restore is presented like a Finder window, but with random folders & sub folders opened. It is really tedious to close the already opened folders & begin to drill down to your choice(s) to restore. I usually find my local Time Machine or clone to get a file is easier. But my Time Machine is not set up for everyday backing up- Only weekly.
2) Also in the interface; if you choose a file, then want another one, it often resets itself to the big mess explained in item 1, above. (Not always, but often)
3) The 'How To' articles on the web site are hard to find. For example, if you type a search for "Set Synchronize Time" you may or may not get appropriate articles. Usually you get random stuff. Once you find the article, they are easy to understand.
4) It uses memory rather greedily while in the background. 413 MB for me. (It uses Java- See the next section...)
Not Sure If These Are Valid "Don't Likes":
1) If you have a sparseimage folder and change one document inside, it backs up the whole sparseimage. If you want to restore a file from inside a sparseimage, you have to download the whole sparseimage & get the file out of it when it arrives. But, Time Machine does that too.
I think that is because, technically, a sparseimage folder is really a giant file. (Just a S.W.A.G on my part)
2) Changes to virtual machines, like a VirtualBox instance of Windows, invoke the entire VM being backed up again. That can take a while. (VM=One Big File?)
I skip the VMs and put copies of newly changed files in the shared folder so CrashPlan can get them. I also use VirtualBox snapshots.
What Others Do Not Like:
1) It runs in a Java environment while doing its automatic background thing. For many, Java is the deal-breaker. I don't know enough to know if I should run away from it based on Java.
2) The interface application for restoring files or changing preferences is also Java based.
It requires you to turn on Java and remember to turn it back off when you close the interface application. (They supply the Java if your OS does not have it)
3) Some people have said it lost their data. I have not had this problem.
4) It does not have a feature to sync between all of their devices. I have not explored this, so I can't give a valid comment.
5) When they decide an OS X version is no longer supported, they pull the DMG off the web site. So if you lose your hard drive, you are out of luck. You do get e-mailed notice before they end support. (I grabbed the DMG for the 10.6.8 compatible version before it disappeared & backed it up to CrashPlan.)
6) You can not see what is being backed up right now. I can see part of the file name in the menu bar icon drop down.
If you think it is worth testing, you can use it for free to back up to a friend's computer via the internet or to a local drive. It uninstalls rather easily and takes Java with it.
So, there it is- My take on CrashPlan.
To be honest, if I find a replacement that does not use Java & is not so memory greedy, but still has deleted file retention and is automatic about backing up only changed files, I'll most likely jump ship.
Hope this is helpful.
I apologize that it is long. I wanted to present all the information that I have available to help people make an informed decision.
Paul