In short, ISPs in the US want to be able to prioritize internet packets on their networks which means, in effect, that the ISPs can control which web services perform faster for their clients. Clearly, there are many people against such an arrangement because they feel that this will limit consumer's choice. I agree in that people will naturally use the faster, more available service over a slower one. In effect, Yahoo! podcasts, for example, will be able to strike a deal with the ISPs to deliver podcasts listed on their directories faster than independent networks and directories.
While I'm not naive enough to think that the Internet will remain the wild west forever, I do think that it's important for podcasters (and everyone else) to have the opportunity to succeed or fail based on their own merit. Destruction of Net Neutrality would introduce factors outside of podcaster's control which can affect listenership, adoption, and eventually success or failure.
If you're not American and think that this discussion doesn't effect you, you might be right, but you're probably wrong. Take a look at where your podcast server is located. While you're at it, make a list of the top 20 applications that you use on the Internet daily. How many of them are located in the US?
If you're a US citizen and want to make a difference, you can go to Save the Internet and sign the petition.
The other side of the house is represented by an organization called Hands off the Internet. They want everyone, including the government, to keep their hands off the Internet. This sounds laudable, but in this case what they're really doing is supporting the ISPs bid. It didn't take me long to find out who funds Hands Off - see how long it takes you.