South Korea developed an online infrastructure fairly early and wanted encrypted transmissions. At the time the US was restricting the export of decent encryption as 'weapons grade' so South Korea came up with it’s own encryption standard called SEED. Because the browsers of the time didn’t support this natively the South Korean government created plugins to enable the functionality: an ActiveX one for IE and an NSAPI(?) one for Netscape 4.

Fast forward and Netscape 4 dies, leaving the plugin unloved and unmaintained. IE achieves market dominance and banks / shops etc start assuming that that’ll be the browser used. Now, when Gecko and Webkit start making inroads outside of South Korea they still don’t have native SEED support which means they can’t be used for secure transactions on the inside. SEED is mandated by the government along with the use of secure transactions for certain operations (online banking for one), so by proxy the use of the ActiveX plugin and therefore Internet Explorer.

Work was recently done to provide Firefox with native SEED support ( https://bugzilla.mozilla.org/show_bug.cgi?id=478839 ) and that should make it in for Firefox 3.6. I guess then we’ll see whether it’s possible for a non-IE browser to gain any market share. Of course, the years of a Microsoft monoculture have caused problems with regards to building sites using web standards…