I roughly remember blackberry apps being able to run in the background and add itself to a list of startup programs and even add in hooks for various OS events (network event etc) and have a background thread handle these events.
Question 1) Is this true?
2) Are these kind of apps allowed in the app world or only available through enterprise distribution?
1) Yes.
2) These kind of apps are allowed if the source is allowed, and the application settings for any special permissions needed are allowed. For example a BES administrator can prevent third party software installation which will prevent all AppWorld applications, and any downloads from the web.