How do you know who’s online? When you launch your IM software, it connects with the services M server and logs you on. The server checks your buddy list to see if any of your contacts are also logged on. Your list updates to show who is currently online. By clicking on a name you can send text-based 55 messages to that person. After you type your note and click on the Send button, the message travels to the IM server, then immediately forwards to your buddy's computer. This all happens in realtime instantly.