Visual mapping tool. Great for mapping complex problems and visual facilitation.
1.4.1
Free to download (http://www.compendiuminstitute.org/download/license.htm)
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.
Open source office suite; free MS Office replacement
Powerful wiki software built to support the Wikipedia project
Wiki with purple numbers, transclusions, and other cutting edge experimental features.
Free hosted wiki software
Web based RSS aggregator and blog reader
Web based photo sharing service
Free, open source software for recording and editing sounds.
URL-shortener (for emailing and general usability)
Hosted online surveys
Simple, easy to use, free wiki service.
social networking for non-social purposes
A free web-based calendar.
Providing free conferencing services include audio, operator assisted, web, and data conferencing solutions.
On-line task manager.
Web-based word processor and spreadsheet tool. Formerly Writely.
Meeting scheduler.
Web-based RSS aggregator