Chromecast: Google Play yes, netflix & youtube no

I use chromecast for youtube and netflix and it works very well. Once I downloaded the app to my android phone and nook tablet, I just start youtube or netflix and once the picture starts on the device you will see a little tv icon and you click on it and it will ask to connect to the chromecast device and you highlight that and it should connect right up. Mine has been great. Wow there was a long sentence in their!