The article focuses heavily on the angle of tantalum ore supply -- but it's worth noting that Niobium capacitors [1][2] have been gaining prominence since the 2002 for the same reason. Niobium-based capacitors have some desirable properties [2] but are roughly comparable to tantalum-based ones; and Niobium ore is much more abundant.

[1] http://www.avx.com/products/niobium/ [2] http://www.imaps.org/adv_micro/2004may_jun/pages/article_nio...