Yahoo! Messenger – a software for the text, voice and video communication on the internet. The software allows to have a private dialogue, communicate in a group chat, exchange the high-quality images or animated files, create the videoconferences, like the photos, etc. Yahoo! Messenger protects the personal data and conversations by means of the data encryption and spam blocking. The software is able to make calls and send SMS to the mobile phones in different countries. Yahoo! Messenger supports the connection of external plugins and modules to extend the messenger functionality.