Well…there's Watchdog Lite and Watchdog Pro. Perhaps Watchdog Lite is what you are referring to?
The Lite version is a trial version of Watchdog Pro. You're limited to backgrounding only two apps with the Lite version.
Other differences with Pro (i.e., the Lite version does not have the following):
Autolaunch apps
Activator Support
Allowing applications to continue running in the background after termination