I think they were introduced around 2 years ago. There's lots of buzz on the interweb about whether they'll be kept, right now the consensus is yes, based on T-

I think they were introduced around 2 years ago. There's lots of buzz on the interweb about whether they'll be kept, right now the consensus is yes, based on T-Mobile's feedback, however, they clearly can't discontinue if you sign up for it, so get going while the going is still good.