Loomio - Loomio helps groups of people make decisions together, online.

Todoist - Todoist is a to-do list that helps you get organized, at work and in life.

PollUnit - Create and customize public or anonymous votings, surveys, free tables, idea collections or audio, video and photo contests.

Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.

Mentimeter - a web-based polling tool for workshops, conferences & events

Remember The Milk - Remember The Milk is a task and time management application for mobile devices.