Q:

clearTaskOnLaunch HowTo?

Reading the Android documentation and some of the answers here have left it ambiguous how clearTaskOnLaunch is supposed to work. Specifically
1) How is the root activity identified? Is it simply the one with the DEFAULT, LAUNCHER or MAIN intent filters? 
2) Launching from "home screen" in the documentation means the OS home screen or applications list, correct? I.e. from not within an application.
3) Does clearTaskOnLaunch clear the activity stack whenever that activity is launched from the home screen, or just when that activity's process is started from the home screen? Because the docs indicate the former, but posts here indicate the latter. I guess this depends on what the definition of "launch" is.
EDIT: 4) Does "clearing" the activity stack mean literally erasing it, or having the activities cycle through onCreate() and finish()? 
I've manipulated clearTaskOnLaunch in every way imaginable with absolutely no effect. I've placed it in my root activity in the manifest, then placed it in EVERY activity just to be sure, restarted my application after killing the process entirely, etc. My activity stack is simply not being cleared. 
Can anyone offer a complete overview on how to implement clearTaskOnLaunch?

A:

Here's a complete response from an Android engineer on Groups: http://groups.google.com/group/android-developers/browse_thread/thread/da024bcaf4e1960f

Reading the Android documentation and some of the answers here (and on 
    StackOverflow) have left it ambiguous how clearTaskOnLaunch is 
    supposed to behave, specifically: 
1) Does "clearing" the activity stack mean literally erasing it, or 
    having the activities cycle through onCreate() and finish()? 

All activities in the stack being cleared will go through the
  lifecycle as  if they called finish().  The root activity will
  generally be kept as-is. 

2) How is the root activity identified? Is
    it simply the one with the 
    DEFAULT, LAUNCHER or MAIN intent filters? 

This is basically the first activity in the stack.  The Intent is the
  Intent  used to start the stack. 

3) Launching from "home screen" in the documentation means the OS home 
    screen or applications list, correct? I.e. from not within an 
    application. 

It doesn't really matter -- it is just whoever sets 
  Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED.  The standard launcher sets
  this  when launching an app from an icon.  You can set it yourself if
  you want. 

4) Does clearTaskOnLaunch clear the activity stack whenever that 
    activity is launched from the home screen, or just when that 
    activity's process is started from the home screen? Because the docs 
    indicate the former, but posts here indicate the latter. I guess this 
    depends on what the definition of "launch" is? 

Whenever it is launched from the home screen.  The fact that processes
  are  killed and restarted should be invisible to the user. 

I've manipulated clearTaskOnLaunch in every way imaginable with 
    absolutely no effect. I've placed it in my root activity in the 
    manifest, then placed it in EVERY activity just to be sure, restarted 
    my application after killing the process entirely, etc. My activity 
    stack is simply not being cleared. 

Settings uses this as an example -- if you go in to settings, dig down
  a  bit, press home, and then launch settings again, you will end up in
  the home  activity instead of wherever you last went to.  It just sets
  the flag on the  main activity of its app. 

