Google treats some ccTLDs (such as .tv, .me, etc.) as gTLDs, as we've found that users and webmasters frequently see these more generic than country-targeted. Here is a list of those ccTLDs (note that this list may change over time).

.ad
.as
.bz
.cc
.cd
.co
.dj
.fm
.io
.la
.me
.ms
.nu
.sc
.sr
.su
.tv
.tk
.ws


Google treats the following as gTLDs that can be geotargeted in Webmaster Tools.
Generic Top Level Domains (gTLDs)

.aero
.biz
.cat
.com
.coop
.edu
.gov
.info
.int
.jobs
.mil
.mobi
.museum
.name
.net
.org
.pro
.tel
.travel