The MPAA and others want HDTV transmissions to contain copy protection signals and "broadcast flags" to prevent trading of recorded episodes and to prevent episodes from being taped. (Apparently, the 20+ years of VHS tape trading has hurt big business sooooooo much that they want home recording and trading eradicated in the future.)
http://www.usatoday.com/tech/techreviews/products/2002-08-12-digital-tv_x.htm has just a tiny sample.
They're also trying to force the system to be totally changed to HDTV format by 2006. I'm enjoying what I've got now because I'm not going to pay into the new system. No way in hell am I going to. Fuck 'em all if they're going to get all fascist on my ass. I'll learn to live without my collection of DVDs and VHS tapes, painful as that will be. Nazi Amer... oops, Corporate America will not have that control.