The document discusses four web applications - Solvr, Posterous, Threddie, and Evernote - that can be used for teaching and learning. Solvr, Threddie, and Evernote are meant for group collaboration and can be used to develop critical thinking and problem solving skills through activities like brainstorming. Posterous is for individual journaling and developing digital communication skills. The document provides information on how each application can be used and assessment questions to evaluate their impact on teaching and learning.