Is there an autorun or scheduler? I have an s3 mini.  It has an app called "My Galaxy" - a marketing adware kind of thing.  It runs without me launching it.  How is that done?  Is there a scheduler somewhere that launches this app?  Can I make changes to that scheduler?

I don't just want to stop "My Galaxy" (I could uninstall it), I want to know how it gets run automatically.
There are many ways in Android of scheduling things to happen later on certain conditions. One of them is the AlarmManager, which lets an app run at a predetermined time, or at a given interval between 15 minutes and daily. This is how most recurring tasks work on Android, such as checking email. There's no user-modifiable control for the AlarmManager: it's up to the app to expose appropriate settings.

Android apps can also register broadcast receivers to be notified when certain conditions are met or when events happen. For example, the email app might also register a broadcast receiver to be triggered when an internet connection becomes available. That way, if it misses its times for checking email because you were offline, it can check email once you go back online.