Text Messaging: Group Text Message I  have a DroidX running Android 2.3.4.  When somebody sends me a text message that goes to other devices too, is there anyway I can tell?  Usually the only way I find out is when somebody else does a "reply all" (probably using a newer version of Android), and I get some random message from a number I may or may not recognize.

Also, what about when I reply to the message?  Does it only go to the person who sent it to me, or does it somehow auto-reply-all behind the scenes?
In 4.2.1 (maybe in 4.2.0) there was an option added to the MMS application to support multiple recipients. 

While you may have been able to see them all the way that William stated, i've never seen that option. 

In 4.2.1 you click on the menu and select "Group Participants". This shows everyone that is included in the conversation. When you reply to a group now, it sends the messages to all participants, not just the person that sent you the message. 

I know this doesn't relate directly to your question as you are not asking about 4.2, but I do not know of a way that this can be done in anything pre-4.2. This feature was discussed a bit because it was the first time android supported this feature.

While you could always "start" a group conversation in any version of android, you could not "participate" in a group conversation with anyone other than the original sender.