Why my Nokia 7230 not play online 3gp or YouTube file?

As you said you have a Nokia 7230 and you are not able to see the online video and YouTube file on your Nokia mobile, so I want to tell you that Nokia 7230 super nova series mobile phone comes with Symbian 40 series operating system and they all support videos I mean online videos you just have to enable the video streaming feature from your mobile phone and then you are able to watch the videos and YouTube videos on your Nokia 7230 mobile phone. For enable the setting of video streaming go to setting menu on your mobile phone and then configuration and then enable the feature of video streaming and then you are able to watch the videos file. I think this information helps you.