I noticed this happen on the iPhone as well, for some reason I don't recall this happening like a year+ ago. But if I send a group message out with a text for funny pic whatever, everyone responds and they say they get the text response back from others that were in that mass text even if they have no idea whom that person is. Or like today I got a text from a buddy and responded, and I got like a dozen text back from others asking who is this (he sent a funny pic out to some people).