2NE1

MTV Iggy has always been sort of more focused on Indie, worldwide, etc sort of music. It's not a recent trend for artists like this to be mentioned on MTV. Even Utada had an old MTV story done on her back in the day, it's just that Korean music is becoming as popular as it is in the US that makes these appearances happen more.

Neither 2NE1 or Girls' Generation have released their US albums or maxi-singles so they're essentially doing "pre-promotion". It also helps that people like Snoop Dog and Will.I.Am. are vouching for these groups and telling the music industry to pay attention to them.