Some 'tinker time' observations/tips ...

Once you add a topic and invite 'friends' to set the focus of the twitter-like bar/column on the right, click on the picture of the person who setup the group.  Or, better yet, click the Topic filter and select only your topic - clears out all other 'conversations' from the circle.

When adding a post one has a little editor for formatting and a button for an attachment.
Attachment does work for images ... that I can confirm ... but dunno about size limitation or file format/type of file allowed/dis-allowed.  The message editor has a check box for 'private message'.

Refresh rates are acceptable and user might have control over those (Time Filter controls).

When the invited gets the invite message and accepts, they are automagically taken to TalkWheel and prompted to enter a password.  That change password box is in the right column - not obvious and could be easy to miss. 
Their account is already created using the EMail address of the invite and they can immediately join the group/room.

In their FAQ they say their app can be embedded, but haven't seen any page that shows how or allows one to copy the embed clip needed.  They also say they have hosting solutions - cloud - or local.

No iPhone/Android app yet, but they say they are working on it.
Wonder how it behaves on tablet devices ... like iPad's and Android's.  Anyone care to share?

Could be a refreshing alternative to 'boring looking' Moodle forums/discussions!

TalkWheel
http://www.talkwheel.com

Video:
https://www.youtube.com/watch?v=QWsZdNCSZUk