performSelectorOnMainThread over Notifications
===

I have some basic doubt's, guess someone will help me out.

Please refer this Question :

I have tried using `performSelectorOnMainThread` , which is calling the updateProgress method in another class and but the label is not updating.

But now I have used the notification like 

    [[NSNotificationCenter defaultCenter] postNotificationName:@"updateProgress" object:nil userInfo:nil];

which seems to be calling the method and also updating the UILabel. Eventhough my problem is resolved, I want to know why the above `performSelectorOnMainThread` didn't worked out for me? Any specific reasons ?