What? Provides online project and image management, CRM, email marketing and instant messaging. Essential business tools.
Why? Glasnost helps you manage all your contacts, projects and images. It will make you more productive and please your clients.
Who? Glasnost is great for sales and operations teams, and for collaborating with clients, partners and suppliers. Built for SME's
How? Entirely web based. Pricing based on number of users and storage requirements. Custom branding. Highly secure.
Diff? Using Adobe Flex technology Glasnost combines a sleek and simple user interface with a wealth of practical functionality. Productivity plus!
What? An Open Source Web Office.
Why? A complete online solution focused on improving productivity, collaboration, communication and management of your teams.
Who? Organizations that want to improve their team work.
How? Technical user: Download it, install it into LAMP, and start using it.
General user: Try it hosted at http://www.fengoffice.com
Diff? Usability, ease of use, clean design.
glasnost21 
OpenGoo EASY TO USE OPEN SOURCE WEB OFFICE