Win

CCleaner is a freeware system optimization, privacy and cleaning tool. It removes unused files from your system - allowing Windows to run faster and freeing up valuable hard disk space. It also cleans traces of your online activities such as your Internet history. Additionally it contains a fully featured registry cleaner.

S3 Browser is a freeware client for Amazon S3 Service. Amazon S3 provides a simple web services interface that can be used to store and retrieve any amount of data, at any time, from anywhere on the web.

Gizmo5 is a free phone for your computer, mobile and tablet.

Skype uses P2P (peer-to-peer) technology to provide voice- and video-based communication with other Internet users.