Online Backups 

Online backups are an important tool, but they are not a perfect solution.

Advantages
Automated, with no action required by user after setup.  Offsite, so protected in case of fire, flood, burglary, etc.

Disadvantages
Slow.  Very very slow. While the initial backup could take less than an hour if you are only backing up your database, it can literally take as long as a week if you are including images.  Subsequent backups are incremental, only sending the changed data.  The service should be run at night, so you won't notice the slowness.  Most services tend to focus on one computer, making it somewhat difficult to regularly restore your data to your home computer to verify the backups. 

MySQL Service
Almost none of the online services allow automated stopping and starting of the MySQL service. Backups can safely be done without stopping the MySQL service because all of the backup services are good at copying locked files.  In the rare case that a locked file causes a failure, it should only affect that one file and should not be a major problem.  But when restoring a database, it is always critical to stop the MySQL service first.  None of the online backup solutions include that capability.

Reviews
Specific backup services are reviewed here in order to help customers make informed decisions.  Most of the products below have quirks.  There are learning curves with each one.

CrashPlan  (currently recommended solution)
www.crashplan.com is highly recommended.
They offer a lot of different options. Their options are best explained on their Store tab: http://www9.crashplan.com/consumer/store.vtl  
The following components should be purchased:
CrashPlan Backup: Free
CrashPlan+ Upgrade (for business use): $59.99 one time
CrashPlan Central (for online use): $54/yr
CrashPlan has many features, including letting you backup to multiple locations, letting friends back up to each other, compression, de-duplication, multiple versions of files, continuous backup, seeded initial backups, etc.

IDrive
This program works fine.  There are multiple interface options, including classic, web, and explorer (virtual drive).  It keeps the last 30 versions of every file, only counting the current version when computing your storage usage.  Timeline restore allows restoring to a specific historical point.  There's also a free backup program (which we have found to be buggy) available on their website that's optimized for backing up to a removable hard drive.  To sign up with or to try IDrive, use this link: https://www.idrive.com/p=open_dental.

SugarSync
Not yet reviewed, but the feature set looks interesting.  Has version management built in, keeping the last 5 versions of every file.  Charges by storage size and does not charge extra for multiple computers.  Automatic multi-computer sync.  Remote access using browser.  Share folders with others.  The shared folders are password protected, but require the other person to sign up for a free trial.

Mozy
The quality seemed high at first, and it comes from a reputable company.  But it had a lot of little quirks that made it hard to use. Mozy does have a rich web management interface, allowing centralized management of backups for multiple computers and offices. The price is very low and you can buy exactly the amount of storage you need and no more.  You buy a key for a computer, and then you use that key during installation of the client program to attach that machine to the service.  WARNING.  Do not attempt to use that same key to install on a second machine.  It might let you, but then the first machine becomes detached, requiring uninstallation of the client program.  Uninstallation requires a computer restart.  The backup process was straightforward enough, although it did cause a computer lockup once during testing, requiring the computer to be unplugged.  To restore the backup to a home computer, the client program cannot be used, not even if you purchase two licenses.  Instead, you must do a web restore.  This involves submitting a request and then waiting for an automated email to inform you that a zip file is ready for download. The zip file has to be manually unzipped.  Unfortunately, their web restore feature has a major bug and rarely works, instead giving an error screen.  Once Mozy is installed, an icon will always be present in the system tray.  The graphical reports in their web interface never seem accurate, either showing more or less backups than were actually performed.  Free phone support available from India 24/7/365.  Mozy is buggy and performs incomplete backups.  Avoid it.

Carbonite
The installer had a bug in it and got stuck halfway through.  We will try to review it again later.  Seems to be used by a lot of people, although it has the known limitation of only allowing restore to the original computer where the backup was performed.

Other Services
Central Data Storage  Specializes in medical and dental offices.