Is the blog as a learning tool?

Here are some examples of blogs:
Blogging as a Professional Development Tool
Blogs & Mathematics
Blogs & Wikis
Brian's Blog
Digital Portfolios
EduBlog Insights
Education World® Blogging Basics Creating Student Journals on the Web
How can children stay safe using blogs
http--www.p1wblog.motime.com-
Little Miss Teacher
Math Playground
Mindy's Blog
Technology Enhanced Learning
The Open Classroom
Think.com - Home
Weblogg-ed
Weblogs In and Around the Classroom
www.primary-teacher-uk.co.uk
7th Grade Math
Al Upton and the miniLegends
Blog of a math teacher