Here is an example of how students used the social media/backchannel client Todaysmeet.com to produce an online conversation.
Day 1/2: Student get assigned a role in Feudalism- They read/researched about their daily life (There are many wonderful sites for this and here is a resource I provided them with) They then put together a twitter wall on butcher paper for their role. For example, the nobles made a Twitter wall for nobles, peasants for peasant. They were quite comical. They also went around and "posted" (wrote) on other people's walls.(Pictures are below)
Day 3: Students take their role and engage in a conversation on TodaysMeet.com. It is a website that allows for Twitter-like backchannels without sign-in or sign-up.