AMS-MAA Invited Address "Using mathematics to better understand the Earth's climate"
Great Maths Teaching Ideas shares maths teaching ideas and resources with teachers worldwide. Founded in July 2010, Great Maths Teaching Ideas has grown into one of the leading maths teaching blogs in the UK. With regular contributions, you can always find an idea on the site for teaching just about any maths topic. Curator of the blog, William Emeny is a full time maths teacher, a member of the TES Maths Panel and author of the best-selling teaching book 100 Things Awesome Teachers Do.
Math, Learning, and Web 2.0 is a technology rich mathematics blog written by Colleen Young. In this blog, Colleen shares her experiences in the classroom, particularly on the use of technology in teaching mathematics.
One  of Colleen’s fascination is the use of Desmos Calculator on which she hasnumerous examples. She is also a fan of Wolfram Alpha. Some of her most popular posts are Top 10 Mathematics Websites, arithmagons,  and online whiteboards.
Math Hombre is the blog of fellow GeoGebra Ambassador John Golden. John has excellent articles about GeoGebra – tutorials and lesson integration alike.  His blog is rich with classroom experiences he shares and he is also an avid user of math iPad apps. He also shares some of the application he used in technology for novice teachers and other posts about technology.
squareCircleZ has articles about math, math education and math technology. Author Murray Bourne brings his extensive experience as an educator to a wide range of topics, including  how we should use technology in math more wisely, how we should write math with better symbols, and how we should change the curriculum so students learn what they really need for the 21st century.
The associated IntMath Newsletter goes out to over 12,000 subscribers (mostly students, many teachers, and a lot of retirees who are looking for “brain food”) twice a month.
There are plenty of articles in squareCircleZ about how math is used in the “real world”. Topics include things like math in science, engineering and daily activities, math in art, math in music, and math in technology.

Technology Math with Technology is good resource of technology resources. The blog belongs to Sue Glascoe. The blog contains resources on animations, Flash tutorials, iPad apps, and many others.
Free Technology for Teachers is not a math blog and Richard Byrne, the author, is not a mathematics teacher, but I have included his blog because it contains numerous links to mathematics resources and software applications. In addition to these resources, Richard has reviewed thousands of free education software and resources. It is not only a place for mathematics teachers to explore, but for all the teachers who want to search for free classroom resources.
I am planning to add more to the list above, so if you know any technology-rich math blog, email me at mathandmultimedia(at)gmail.com.
http://mathandmultimedia.com