Pixelmator is a popular commercial image editing software for Mac OS X users.
Password Manager, Auto Form Filler, Random Password Generator & Secure Digital Wallet App.
Hugely popular Mozilla community providing support for Firefox, Thunderbird, Seamonkey and other well known Mozilla products. Over 350k members and 4 Million posts.
Fujitsu is a hardware and IT services company focused on providing IT-driven business solutions. Their community forum is powered by phpBB.
KDE is mainly known for producing the KDE Desktop Environment (used in Kubuntu) for Linux.
It is the Italian Community for Ubuntu, a popular open source community operating system based upon the the Debian Linux Distribution.