Change your status and set it as busy, not available, etc. You can choose to be as invisible or to write your own status to let your friends know something important.
The most interesting feature in Yahoo! Messenger is that one that allows you to share images and emoticons right from your iPhone or iPod Touch. Very comfortable.
Yahoo! Messenger is a very interesting application for any kind of user because it lets you keep in touch with your friends, no matter if they use Yahoo or Windows Live Messenger.
Compatible with iPhone, iPod touch and iPad.