The tools available to you will differ from Course to Course depending upon what has been enabled/disable by your lecturer.
A blog is intended to be used for diarised type commentary by an individual or group that is accessible to all users of the module for review and comment. A blog post can include text, images, links, multimedia, mashups, and attachments. Blogs are an effective means of sharing knowledge and materials created and collected by the group in the course. You can post entries and add comments to existing blogs.