I think that using a blog in an educational setting is something that facilitates deeper learning associated with the subject involved, as well as more student involvement in that particular subject. I would like to teach second languages in high school (I will focus on German in this entry). I think that blogs have an excellent place in these subject areas.
One idea for things to include on a second language blog would be resources. Through my studies, I have found many resources that would be beneficial for someone using a second language. Things like dictionaries, thesauri, and grammar websites can help a student with their reading comprehension, writing and definitely their speech. Second languages lend themselves especially to this kind of online resource library because they have information that most students are unlikely to be familiar with or have immediate access to at home.
Cultural aspects of the language could be introduced as well in the form of quick cultural facts, history website links, pictures from my (and others') travels. I found an excellent blog online that exemplifies this kind of cultural approach to language learning. It is a Spanish learner/teacher website, but the same concepts apply:
http://www.spanish-teaching.com/blog
There are other websites out there that have interesting ways to practice the language. For example, the link below is to Brothers Grimm fairytales that are presented with the German text alongside English translations.
http://www.fln.vcu.edu/grimm/
There are also German newspapers and online magazines that could be provided as links.
To take this deep learning to another step, I think an amazing thing to do would be to make contact with a class in a German-speaking country and exchange blog addresses. In Clarence Fisher's “Remote Access” blog, here:
http://remoteaccess.typepad.com/remote_access/2006/05/blogs_invitatio.html
he talks about using Blogs as a tool to connect to other cultures and other “lives”. This is a great way to show the practicality and the amazing potential of learning another language by getting to know people that speak it.
On a more personal note, blogs can be used for a teacher to connect with their students and vice versa. What comes to mind for me is keeping a journal of German literature/media that the teacher and students personally consume. This can model life-long learning on the teacher's side and help the relationships between teachers and students by creating a positive interaction.
There are also many practical uses for blogs to help the mechanical aspects of classes – such as assignment dates, chapter reviews, handouts and schedules. The link below leads to a site where the writer summarizes these practical uses nicely:
http://crookedtimber.org/2003/09/15/the-street-finds-its-own-use-for-things
Now, blogs do not come without dangers. Luckily, when one is dealing with students of the high school age, they can usually grasp what these dangers entail. Many of the dangers inherent in student and teacher blogging revolve around privacy issues and respect issues (one has to be sure that both teachers and students are being respectful of each other at all times to maintain the positive blog experience) The link below not only details many of the dangers, but offers tips for creating safe blogs:
http://www.isafe.org/imgs/pdf/education/Blogging.pdf
Some of these tips are about abstaining from including any personal information that would help someone dangerous find you. Others revolve around avoiding slander and gossip about fellow students.
Though there are inherent dangers in using online technology such as blogs (especially if it is kept open for something like blog sharing with another class) if proper steps are taken to protect student and teacher safety, privacy and mutual respect, it can be a wonderful tool to deepen student's learning and facilitate necessary classroom mechanics.