Like other instant messaging systems for portable devices, Hike allows you to maintain individual conversations with your friends or create group chats. Anyone can participate in a group chat with their favorite messaging system, even if that's not Hike.
Other features included in Hike allow you to send quick voice messages, similar to using a walkie-talkie, and to use stickers in your conversations.
Hike also has an option that you can use to limit who can see the last time you were connected. You could make that information visible to a group of close friends, then add and remove people as you see fit.
Hike is a great instant messaging tool that includes tons of options. And, everything is run from a clean, attractive interface.
Requires Android 2.2 or higher.