Not so much a particular class of tools as an emerging pattern of collaboration, the term "multi-channel" refers to when people collaborate in groups using several types of tools simultaneously, e.g. a telephonic conference call where everyone in the group is simultaneously also logged into a chat group and adding material to a wiki. The chat room is used simply to indicate when one wants to say something and for the facilitator to indicate who should talk next while the wiki is used to contribute material such as links.
Face-to-face meetings are also increasingly being conducted in conjunction with collaboration tools such as Wikis or electronic whiteboards in which all group members can write.
James Farmer has set out a simple activity outline describing how to present a live (or online audio) lecture in conjunction with a chatroom, promising that "you'll get FAR more questions / ideas and thoughts than you would in a regular lecture".
Increasingly common at presentations, such as at conferences for example at, is the existence of one or more 'backchannels' - chat groups maintained by audience members via laptop computers commenting on what the speaker is saying, providing related links and so on. In a blog post Learning From (and About) the Backchannel Liz Lawley discusses positive and negative elements of this and links to other discussions on the topic. The most obvious benefit of a backchannel is that it makes a presentation less of a one-way affair. It also tends to bring together people who would not have approached each other otherwise.