HEY - Email at its best, new from Basecamp.
My Personal Kanban - This is a one page HTML/JavaScript application for people who would like to use simple and basic...
InstAddr - Disposable email address application.
TaskBoard - A Kanban-inspired app for keeping track of things that need to get done.
Horde - Horde Groupware is a free, enterprise ready, browser based collaboration suite.
buckets.co - Feature rich kanban board collaboration platform.