First of all I want to appreciate that you are interested in posting tamil poems when no one really cares about it. Posting tamil fonts is really simple if you follow the following.
Just google Azhagi tamil software and install it in your computer. Websites cannot recognize tamil fonts if you type it and paste directly. Instead you need to define an unicode which is the universal format. So when you running azhagi program just press f10 to get the unicode pad wherein you can type tamil poems or whatever you like and paste it in any web pages as it is unified now.
Thank you. Keep posting.