after tonights session I would like to express a few thoughts on the comparative experiences between these two communication methods.
Although this would not be fair comparison as they serve different purposes (Twitter as a largely asynchronous social networking tool versus the synchronous communication tool Skype) they could nevertheless be judged in regards to their effectiveness as learning tool within this module.
Personally I make Skype the more effective one mainly due to the immediacy of the dialogue. Despite the lack of depth of content a sense of real debate prevailed despite the fact that most messages and the resulting threads were on the short side 
This would imply that it is not so much the limitations on message length to 140 characters which many people struggle with in Twitter but more the asynchronous nature of the communication thus limiting the experience of involvement and debate. This is underlined by the fact that it is difficult to comment on previous Twitter posting as it is difficult to refer to the original message in a meaningful way as is normally done by repeating the message ahead of  the reply. 
Importantly the sense of learning community was shining through much more readily in Skype than Twitter, an important aspect in distance learning.
This leaves Twitter with just being a repository of brain waves and ideas, and relevant Web-links, i.e. as a ‘broadcast’.
Twitter itself my find better uses for example in small group brainstorming using narrowly defined hashtags, followed by a Wiki to summarize the main points, or else to following broader e-learning communities or relevant interest groups at Edinburgh University or elsewhere with relevant subject relevance.