If you have many apps installed then I can see the potential of having an automated service for that.
If you don't have that many then just launch each app. Or mark them all in one swoop - Sort by Last Modified Date with Spotlight in the Applications folder(CMD+F) and open those by selecting them all and CMD+O - prepare for a fine launch festivitas. Update..
So my apps are either from the MAS (which obviously auto updates) or downloaded direct from the developer. But I can't think of a single other app I use these days that doesn't automatically check for updates.