Viber - Free and secure calls and messages to anyone, anywhere. Keep your conversations going no matter where you are.

Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.

MiVoice Business - MiVoice Business is a business communication platform that delivers voice, messaging, mobility, presence, conferencing, collaboration and applications.

Shutter - Shutter is a feature-rich screenshot program.

Screenleap - Screenleap is a web app that lets users share their device's screen over the Internet. These screens can be a desktop computer monitor or a smartphone screen or anything else that can load a web browser. Read more about Screenleap.

MWSnap - MWSnap is basically a free to use Windows snapping tools that are used for snapping any part of the screen that is currently displaying on the front of all opened programs and windows.