South Koreans are being advised by their Government to postpone their adoption of Windows Vista until they're sure they'll be able to bank online and other web activities. The problem it seems is that Korea has almost universally adopted ActiveX technology for all of their "online banks, portals, game sites and malls". Vista makes changes to IE7 that breaks many of those ActiveX web applications until changes and updates are made to the websites to fix these problems.
Microsoft is working with many of these key financial institutions and online portals but most of these web sites won't be done until some time in February. Until that time, Korean citizens are advised to hold off on Vista and check the Ministry of Information and Communication website for a timetable of fixes for all the major portals. Meanwhile, ZDNet Korea is reporting that an organization called "Open Web" has filed a lawsuit against financial institutions and the Korean government for its "monopolistic endorsement of the Microsoft IE".
The key reason ActiveX is mandated by financial institutions is that Korea has its own national encryption scheme called SEED that is used in place of SSL. The reason this came to be stemmed from the fact that US export law in the late 1990s didn't permit the export of web browsers with more than 40 bit encryption. This meant that an ActiveX SEED plug-in was used in place of browser SSL. While there are Java and Netscape implementations of SEED, it was almost never implemented. ActiveX is so dominant that KFTC (Korea Financial Telecommunications and Clearings Institute) won't even assign users security certificates unless they're using Internet Explorer with ActiveX. KFTC is the financial institution along with the Korean Government named in the Open Web lawsuit.