It'll probably start with pared down news servers (alt.binaries.bye-bye), and proxies which block known warez sites.
Then the floodgates will open, and they'll try to trim any bandwidth hogs they can...once they are imbued with newfound power, expect to see ruthless tactics like incomplete DNS. I was in China last month, and was amazed at the hoops I had to jump through to get to some sites. If a gov't can do it effectively, private industry can do it blindfolded.
You can get around most of the cable companies known limitations, but the fact is you shouldn't have to, ever. My grandma doens't spend much time on alt.bianries.punk, but she should have the ability to if she gets out of her big band on vinyl 78s "phase".