TN visas are renewable yearly, but holders of TN visas are ineligeable for green cards. The TN visa is a non-immigrant visa while the H1B visa is dual intent: non-immigrant and immigrant. The other issue is that you are required to have a degree in the field of intended employment. You can't come to the U.S. and do any job. It must be related specifically to your degree. Nor is it an amnesty bill. You must apply for the visa when you enter the country. You cannot apply for it from inside the U.S. The author of this article is doing some major spinning and is misrepresenting basic facts.
I read Findlaw's description at:
http://library.findlaw.com/1999/Oct/1/126350.html
and you are quite right. Thank you.