At THATCamp CHNM  this year, Mark Sample  proposed a session on "Building a Better Blogging Assignment" . Those present shared their experiences from assigning blogs in past courses and also exchanged models and ideas for assignments that best fit their course objectives. Some use blogs in seven week online courses, while others have incorporated blogs into the semester-long physical classroom or hybrid courses. While you can draw your own conclusions by examining the collaborative notes  started by Trevor Owens , the guide below presents my own summary on how to design and implement a blog assignment for your own course.
First, realize that the blog is not a genre but a platform. While students certainly bring a set of perceptions to a Wordpress dashboard or how a blog post should read, the blog is simply a platform for text and media. Students can post long-form essays, poetry, or any other form you want, you just have to guide them. It is always a good idea to assess your students' expectations of blogs and to discuss opportunities like developing an online persona, engaging with a public audience, or experimenting with something like a "Blessay ".
Let your course goals determine the blog assignment. You wouldn't assign a paper without aligning it with your course goals, so think carefully of how a blog assignment will fit with the class objectives. A potential strength of a blog is to increase the visibility and readership of your students' work, even if it is just within the confines of the course. This might be beneficial in a course on public history, for example. If you don't want your students reading each others' entries, you might just consider using something like dropbox  to accept their documents online.
Experiment with roles. At the THATCamp session, someone brought up Randy Bass's technique  of having students rotate between three roles: first readers, respondents, and synthesizers. This gives students the chance to generate the main content, have their peers comment on their ideas, and to see how a third group synthesizes the discussion. Others roles came up in the session including 'seekers' who post related content and supplemental material, 'in-class hosts' to lead the discussion if you meet physically or over Skype/G+ Hangout, and even rotating a role where students take that week off and simply observe.
Find a model to guide your development. This will be highly dependent on your discipline and course objectives, but doing some research to locate similar courses can pay dividends. I have been looking at the student posts at Jeff McClurken's Adventures in Digital History  course at UMW not only to get a sense of how their content looks, but also to see how they assess their posts and projects in light of the course goals. Digital Storytelling 106  strikes me as an excellent model for developing goals and methods to help students build a digital identity and create media.
Provide students with models of what you want. One of the most challenging aspects in using a course blog is to have students meaningfully engage with their peers' posts. Grammar girl has an excellent guide that you can give your students on "How to Write a Great Blog Comment" . The guide contains nine easy rules and your students can listen instead of reading if they prefer (there is also a cover of Sir Mix-a-Lot's 'Baby got Back' called 'Yo Comments Are Wack! ' at the end of the post). Think about the elements you want students to produce in their blog posts and provide solid models for each.
Finally, peruse Mark Sample's post on "Making Student Blogs Pay Off With Blog Audits ". This not only allows you to assess the blog's place in your course, but also encourages your students to reflect on how the platform affected their ideas and learning.
Do you use a blog in your course? Do you have any resources for helping others evaluate or incorporate the use of a course blog?