I love yahoo messenger. It is a lot of fun especially with the latest version.
You get to pick all these neat backgrounds for your messages like floating hearts on a pink background, fish swimming in water. It makes it alot of fun to type on.
Yahoo has voice which is very clear and you can talk just like you were on the phone. It also has a web cam feature for those that like to use it and it is nice to see who you are talking to.
You have your friends list and you can add people on as you wish. If there are people you dont want to talk to you can put them on an ignore list so you will never get another message from them.
You can sign on invisible if you wish and then only let the people you want to talk to know you are there by sending them a message otherwise they cant see you.
You can send files through to each other such as pictures right while you are talking to them.
I really like this chat program and would recommend it to anyone.