The introduction of the new curriculum should hail a new approach to student learning. Using blogging as a teaching tool crosses many of the Visions, Principles and Values outlined in the New Zealand Curriculum.
On the surface it is clear that blogging encourages computer literacy and language literacy through reading and writing.
Dig a little deeeper and you will find many other opportunities.
Once you start blogging you are a connected international citizen - add a Clustrmap to your blog and you can see the places in the world where people are reading your work.
Get others to read your blog by reading theirs and leaving comments and links, start a discussion with someone from another country and culture.
By sharing your ideas you become part of the 10% of content creators on the internet. Think of it as giving something back to the community.

