How I Use It
I am not a teacher, but have used this program myself, and my 5th grade daughter has used it in order to get some beginner lessons on coding. We have used the program both at home and at school.
My overall opinion of Code.org is that it is a fun and engaging way for any student (minimum grade 2) or adult to get a basic overview of what coding is and how it works.
What I liked is that the individual programs take approximately one hour to complete, and they are easy to break up into smaller lessons or sections (each program has about 20 individual mini-levels within it). Code.org uses fun cartoon characters that younger students are familiar with, and can often create a feeling of gamification while learning. The mini-levels increase in difficulty, but each level has hints and tips to help students along. Adults can find the program easy to follow as well, and would benefit from starting at Code.org for introductory lessons in coding before moving on to more advanced programs.
What I didn't like is that several levels were much too advanced for grade 2 (as an adult, I struggled with a few mini-levels myself). The advanced mini-levels might be better for small group or whole class collaboration first, and then individual practice afterward.