Dafydd ab Hugh has a good piece explaining why South Korea should not have paid off hostage takers in Afghanistan:

And there you are: What you subsidize, you inflate… and that’s true whether the “payment” is money or just prestige. As sources in the article point out, the mere fact that a real government — the Republic of Korea — sat down and negotiated with the formerly moribund Taliban tremendously raises the stature of the latter. It will probably help in recruiting, it might force President Hamid Karzai to take them more seriously, and if we’re really, really unlucky, might even lead to some kind of power-sharing arrangement. Thank you, Mr. Roh.