- Twitter is a microblogging service that allows users to post short messages called "tweets" that are up to 140 characters in length. Tweets can be posted from the Twitter website or via text from a mobile phone. - Blogs are websites that allow people to post various entries like commentary, descriptions of events, graphics, or videos. Blogs provide opportunities for students to interact with each other and teachers. - While both have advantages like sharing knowledge, Twitter has disadvantages like spam messages and requiring abbreviations. Blogs have disadvantages like needing internet access and regular updates. The author would not use Twitter or blogs as a teacher preferring face-to-face communication.