It is a verry important topic About Admob

// This code works on Android API level 1 (Android 1.0) and up.
// Tested on the latest (at the moment) API level 19 (Android 4.4 KitKat).
// In the main activity of your app:

public class MainActivity extends Activity 

  (...)

  
override[/p]
  public void onStart() {[/p]
    super.onStart();[/p]
    final SharedPreferences settings =[/p]
        getSharedPreferences("localPreferences", MODE_PRIVATE);[/p]
    if (settings.getBoolean("isFirstRun", true)) {[/p]
      new AlertDialog.Builder(this)[/p]
        .setTitle("Cookies")[/p]
        .setMessage("Your message for visitors here")[/p]
        .setNeutralButton("Close message", new OnClickListener() {[/p]
          override[/p]
          public void onClick(DialogInterface dialog, int which) [/p]
            settings.edit().putBoolean("isFirstRun", false).commit();[/p]
          }[/p]
        }).show();[/p]
    }[/p]
  }[/p]
}[/code:3tcp4004][/p]
[/p]
And for Ios[/p]
[/p]
[code:3tcp4004]// This code will work in iOS 2 and up[/p]
// (spoiler: you're not going to need anything below iOS 6).[/p]
// Tested in iOS 7 [/p]
// In your app's UIApplicationDelegate:[/p]
[/p]
[ul][/p]
	[li](BOOL)application:(UIApplication *)application[/li][/p]
[/ul]    didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {[/p]
  (...)[/p]
  NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];[/p]
  if (![defaults boolForKey:@"termsAccepted"]) [/p]
    NSString *message =[/p]
      "Your message for visitors here";[/p]
    UIAlertView *alert =[/p]
      [[UIAlertView alloc] initWithTitle:@"Cookies"[/p]
                                 message:message[/p]
                                delegate:self[/p]
                       cancelButtonTitle:nil[/p]
                       otherButtonTitles:@"Close message", nil];[/p]
    [alert show];[/p]
  }[/p]
}[/p]
[/p]
[/code:3tcp4004][/p]
I think it is a lot of people having trouble with this.[/p]
And yes me too .[/p]
Thank's