A blog provides a place for students to express their thoughts and discuss course material. In a forum, you can restrict students from creating new threads. In a blog, students have the freedom to create new entries.
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Combine blogs and wikis to complete the learning cycle
In a blog, entries and comments are organized chronologically. This makes a blog a good tool for publicly documenting and discussing a journey, or continuing a project. A wiki is organized as per topic. This makes it a good tool for categorizing and organizing knowledge. While you guide the students through a journey or project, you can have them blog about their experiences. At the conclusion, you can have them assimilate and organize their knowledge into a wiki.