Here are 15 free online collaboration tools and apps to try today:

Keep and Share – Keep and Share is a group file sharing system. Accounts are password-controlled and secure enough to store sensitive information.
Wridea – Wridea makes it easy to collaborate and share ideas with colleagues, team members, and fellow learners. This brainstorming tool organizes and categorizes ideas onto different pages, provides unlimited storage, and allows users to comment on topics and ideas.
Writeboard – Whiteboard is free collaborative writing software. It can be used to write, edit, track changes, and rollback to previous versions.
Twiddla – Twiddla works very well for online meetings or co-browsing. Groups can use it to mark-up and comment on web pages, images, and other content.
Spicebird – This open source platform is an all-in-one suite of communication tools for people who want to collaborate online. Features include email, instant messaging, and an online calendar.
Stixy – Stixy works like an online bulletin board or whiteboard. It offers a work space where you can place content and collaborate with other people on the web.
ReviewBasics – This free online service is great for people who are collaborating and editing different types of content. ReviewBasics allows users to share, annotate, and markup everything from images and videos to documents.
EditGrid – EditGrid is a web-based application that works a lot like Microsoft Excel. Special features include sharing, collaborating, and publishing capabilities.
ooVoo – ooVoo offers a free 2-way video chat service and a 6-way text chat. The site can also be used to record and send short video messages.
Palbee – Palbee is a free video conferencing tool with multiple capabilities. Users can conduct video meetings with other people or record a video presentation for later viewing.
GroupTweet – GroupTweet is designed for Twitter users who want to be able to communicate and collaborate privately.
Edmodo – Edmodo is rather like a private Twitter. Students and teachers can use this free (and private) microblogging platform to communicate online. Edmodo also provides file sharing and file storage.
SimplyBox – SimplyBox allows users to capture specific images, text, and video and then organize their finding into an easy-to-share box. Conversations and comments can then be placed around the box and shared once more.
Mikogo – This free desktop sharing software can be used for online meetings, web conferences, presentations, remote support, and other collaborative efforts. Mikogo is incredibly simple to use and download.
Vyew – Vyew is a relatively new collaboration platform that can be used for webinars, online conferences, and real-time learning and instruction. No installation is required and all activity can be tracked and logged.