In Windows Phone 7.5, there was an option to receive group text messages and see all the other recipients. In Windows Phone 8, that was removed and it was incredibly confusing to receive a group text message. After getting the [collapse]original message you start receiving replies from people you’ve maybe never even talked to before.
That was all fixed in the latest update which I received on my HTC 8x last week. Go into Settings > Applications > Messaging and then enable Group Text all the way at the bottom. It seems crazy that it took so long for this feature to return, but I’m glad it’s back. The update also enabled the FM radio that has been lying dormant in the phone.