Localization
Very extensible CMS platform based on PHP and used by many NGOs - "Community Plumbing"
Firefox is the popular open source web browser from Mozilla
Free/cheap Internet telephony and handy IM tool.
Web based social bookmarking lets you share online finds and discover new ones. Ground zero for tagging.
Web-based project management tool
Google Earth combines satellite imagery, maps and the power of Google Search to put the world's geographic information at your fingertips.
Web based photo sharing service
Free, open source software for recording and editing sounds.
A freely distributed piece of software for such tasks as photo retouching, image composition and image authoring.
URL-shortener (for emailing and general usability)
Gmail is a web-based email with very user-friendly interface and huge storage capacity
A free web-based calendar.
Facebook is a social utility that connects you with the people around you.
Twitter is a global community of friends and strangers answering one simple question: What are you doing? Answer on your phone, IM, or on the web.