"Island hopping" is the name of the current trend in spamming. Now that anti-spam filters and blacklists are wise to the spam domains in the typical .com, .biz and .info namespaces, they're switching to domains of small island nations such as Sao Tome and Principe (.st) and Tokelau (.tk) to bypass them.

The malware reasearches at McAfee first caught onto this trick after noticing an unusual number of .st domain name registrations. This raised a red flag for them, and further research showed a migration of spammers to domains for small island nations, particularly:

Spam from these domains has been increasing -- here's what an article in EFYTimes has to say:

"This new trend is another example of spammers' relentless quest to spread their abuse of Internet domains far and wide," said Guy Roberts, senior development manager, McAfee anti-spam R&D team. "Some of these islands have dozens of spammed domains per square mile."

Link