Walkaround is described as 'variant of Wave, based on the Apache Wave code base, that runs on App Engine. Walkaround can import waves from wave.google.com to allow users to keep working with their data after wave.google.com is shut down' and is an website in the Network & Admin category. There are three alternatives to Walkaround, not only websites but also apps for SaaS, Android, Chrome OS and iPhone. The best alternative is Moo.do, which is free. Other great sites and apps similar to Walkaround are Rizzoma (Free, Open Source) and kune (Free, Open Source).
Email and IM are linear contextless communication tools. Messages pile up and get lost or become redundant. There's no way to keep track of who replied to what, or which version of the conversation is the newest.