I’ve noticed that many DVDs explicitly state “not viewable other than in the United States” or “not viewable in England and Europe”. Is this because of the voltage of the DVD player or… what exactly? Is there a similar problem with CDs or VHS tapes?
It’s probably because of regioning. Look at this map to see all the regions. Hollywood invented this system to keep people in one region from buying DVDs from another region before the movie had a theatrical release. So for example, say a movie is released in the US and has its run and is released on DVD in America before it’s released theatrically in Australia. The regioning system is there to prevent Australians from just buying the DVD from Amazon here and watching it at home. There are region-free players (I own a Malata myself) that can get around this limitation.
There are also different TV standards - NTSC (North America and Japan) and PAL (pretty much everywhere else). Many DVD players can convert a NTSC disc to PAL output or vice-versa. With videotapes it’s much harder - you’d need either an external NTSC\PAL converter or a VHS player than can play both types. The last time checked those players are $$$ 'cos it’s a niche market.
CDs have no limitations like above.
That’d be the reason. Mostly it’s to shaft consumers - movie companies can charge what the market will carry without worrying that people will import from someplace they’re charging less.
For some reason, the idea that DVDs must be “regioned” has caught on to places it’s just dumb. For example, I can’t get a copy of Bottom 'cause the BBC only releases it in region 2, when it would make much more sense for them to use region 0.
Nanoda: But isn’t regioning required (like CSS) for all countries where regioning isn’t specifically illegal (like New Zealand, IIRC)?? Not that I’m arguing with you - I had to shell out $279 for a region-free player just to watch the director’s cut of Lock, Stock and Two Smoking Barrels.
“Required”. Feh. Wouldn’t surprise me. Buncha RIAA chowderheads.
Disabling the region features of your stand alone DVD player or on your computer is not illigal. The movie companies are just giving us consumers a hard time to make it difficult in this digital era. There have been numerous threads about this.
Also, most modern 100Hz tv sets are perfectly capable of handling both PAL and NTSC outputs from the DVD player. I just got a 32" Samsung the other week for $995 which do this just fine.
Many DVD players can be ‘fixed’ by just keystrokes on the keys on the front or remote.
The latest DVD I bought was £60 ($100) for a UK version or £70 ($115) for a universal one; the only difference was a plastic sleeve with a photocopied (downloaded from the net) set of instructions for keystrokes!
Now I can play DVDs from anywhere.
The latest attempt is to make such patches impossible, but there’s always a way around whatever they do- got to love the net.
No, but that’s what Region Coding Enhancement is for. 
you could always buy the dvd and if it will not work in your region download the divx of it. since you own the movie that should be legal.