ELA and Social Studies
PenPal Schools

Give students global perspective with pen pal projects in any subject
Bottom Line: This is a thoughtful, ready-to-go platform that facilitates authentic and safe cross-cultural collaboration.
NaNoWriMo Young Writers Program

Wildly engaging contest turns students into novelists in 30 days
Bottom Line: A thoughtful adaptation of the famous and fun grown-up novel writing contest, NaNoWriMo Young Writers Program is brimming with advice and encouragement as well as classroom support.
LitPick

YA review site gives students a real-world, although ad-driven, outlet
Bottom Line: LitPick is a decent place for YA lovers to discover and discuss books, but the site is in need of a refresh and features a lot of promotion/ads.
Kaizena

Nifty add-on enables audio and text feedback in Google Docs
Bottom Line: If your classroom relies a lot on Google Docs, this might just be the feedback tool you're looking for.
Youth Voices

Aging online community hosts authentic student writing
Bottom Line: With some patience and understanding, this could be a good space for supporting healthy student expression.
Write the World

Global community helps young writers write, revise, think, and grow
Bottom Line: With interest-based writing prompts and thoughtful feedback from peers and pros, this is a great tool for writing for authentic audiences.
Science, Technology, Engineering, and Math
Defined Learning

Stellar collection of STEM resources supports project-based learning
Bottom Line: Excellent, well-thought-out resources for developing problem-solving skills in the classroom.
CueThink

Social approach to problem-solving promotes deep math learning
Bottom Line: An innovative, community-based platform that helps students plan, strategize, and collaborate.
Tuva Labs

Dynamic data-exploration tool offers large collection of data sets
Bottom Line: Partner with another teacher (preferably a data whiz) and work together to develop cross-curricular activities.
Mosa Mack Science

Engaging design challenges turn kids into actual science detectives
Bottom Line: A thorough, engaging way to weave some engineering into your middle school science lessons.
Inq-ITS

Virtual labs epitomize the NGSS Science and Engineering Practices
Bottom Line: Earth, life, and physical science simulations coach kids through the NGSS Practices.
CanFigureIt Geometry

Flex your deductive reasoning muscles with geometric proofs
Bottom Line: A really good way for math students to learn about proofs and explore them from a number of angles.
Desmos

Powerful graphing calculator deepens understanding with visualization
Bottom Line: Desmos combines interactivity, visualization, personalization, and collaboration to deepen students' understanding of geometry and graphing concepts.
NOVA Labs

Online science, mastered: exceptional content within meaningful tasks
Bottom Line: Serious, sophisticated science engagement -- but be prepared to take some prep time to connect these labs with your classroom.