The videoworld is ruined by a plethora of non-compatible Television/Video Standards. As always the yankees wanted their own system and named it NTSC, after The National Television Standards (or System) Commitee (of the Electronics Industries Association) (or Never The Same Color Twice). It's also used in Canada, Mexico and Japan. The system has a variant, NTSC 4.43.

Most West-European and Latin countries carry the PAL-standard, which stands for Phase Alternating Lines (or Phase Alternation by Lines or even Picture Always Lousy- which is bull of course). This also used to be split up in PAL-A and PAL-B (with the UK having PAL-A).The Sound Modulation of these systems is not the same. If you play a PAL-B tape on a PAL-A (UK) video you won't get sound. There still is N-PAL (used in Argentina, Paraguay and Uruguay) and M-PAL (used in Brazil) which is almost exactly the same as NTSC. Australia also has PAL.

Yet France, Poland, Russia and some other East-European countries have SECAM (Sèquentiel Coleur Á Mèmoire / Sequential Color and Memory) and some other MESECAM (... -used where SECAM is used, and in Greece). The difference between these is only the Colour Signal Frequency. For the games of the Atari 2600 VCS there is no difference at all with the PAL versions (i.e. no separate SECAM games were produced)

The difference between all these confusing systems lies in the Frames per Second Rate (FPS), Colour Signal, Field Frequence and the Horizontal (Scan) Lines. NTSC uses 30 FPS and 525 lines, PAL 25 FPS and 625 lines (PAL-A has 25 FPS and 405 lines), and SECAM 25 FPS and 819 lines, plus uses a different system to encode it's colours (the Colour Signal Frequency again). For those of you that are not confused yet: Film runs at 24 FPS (except for 8mm, this runs at 18 FPS). But no one plays his 2600 from film I hope.

Historically, the different systems (in Europe) owe a lot to political considerations. Basically, many countries didn't want their citizens to be able to pick up broadcasts from neighbouring countries, so they adopted different standards. The PAL-A and SECAM story is a very good example of this. There are also the technical reasons -different standards were adopted to minimise the risk of interference between broadcast signals.

The fragmentation into separate markets became an issue in the late 1970s when home video recorders came onto the scene, long after the standards had been set. For now, the standards won't merge mostly because of money. Different systems keep the markets seperated, and the more markets, the more money there is to earn. The rise of the DVD (Digital Versitile Disc), DTV (Digital Television) and HDTV (High Definition TV) is not changing a thing. DVDs are produced for different standards and different areas. To make sure the movie-studios are making huge profits, special code with the release date for that specific area imprinted, so that the DVD will not play until that date. European DVD players will play American (NTSC) discs, US discs won't (and should there be a reason?). Meanwhile, in France, moviebuffs can buy their favorite films on DVD at the local supermarket, while the support and number of titles available in the Netherlands is pathetic and hopeless.

The NTSC standard was devised in the 40's, and the only major update since then has been the addition of color in 1953. NHK of Japan (a state-owned broadcasting company), who adapted the American standard was the first to develop a more sophisticated follow-up of a higher quality. While U.S. corporations were sitting on their butts, Japan and Europe were gathering money for further research. The companies in the States finally caught on as well. However, the process of discussions, proposals and counterproposals has taken up to 1993, when a Grand Alliance reached a compromise for HDTV. As of now, 18 new (HD)TV formats have been submitted (by various companies) to the U.S. FCC (Federal Communications Commission, who issues broadcast licences and provides the bandwith).
As you can see, it takes a long time before the crappy screens you are looking at will finnaly be updated into something bearable, whatever region you're in. It's really only getting worse. No doubt that this will influence the future of the game industry in a bad way.
If you want to know more about this, there has been quite a revealing article in WIRED magazine ("The Great HDTV Swindle"), and if you're really into die-hard technical Film- and TV-schtuff you should become a member of the SMPTE (Society of Motion Picture and Television Engineers). Actually,