I'm not sure how they chose that list.

It's not a great article.

Other people have mentioned Geexbox and XBMC which are useful media centre distributions.

Slitaz is a cool minimal distribution, with excellent internationalisation. (It's amazing what they fit in to such a tiny package.)

Tinycore / microcore are great minimal distributions, but I don't know how much they're being developed at the moment.

Exherbo looks suitable for masochists. (http://exherbo.org/)

Arch / Gentoo / Linux From Scratch are great for people who want to learn Linux or who know exactly what they want.