Using Apps in Instruction

Recently, I found two interesting graph that guides instructors using Apps in instruction.

The first one is the Periodic Table of iPad Apps (please click here for a high revolution version). It divides 82 Apps into eight categories associated instruction: creativity, demonstrating, learning, teaching, computing, collaboration, numeracy, and literacy. Checking familiar social media Apps in this table, we could find that:

Twitter is good for teaching;
Edmodo and Pinterst are good for collaboration;
Interestingly, Facebook is not in the category of collaboration of the table.

The second one is the Padagogy Wheel 4.0  (please click here for a high revolution version), which based on Bloom's Taxonomy, i.e., understanding, remembering, applying, analyzing, evaluation, and creating. Also, some familiar social media Apps are also in the wheel:

Twitter is good for remembering and understanding;
Facebook, YouTube, Edmodo, and Blackboard are good for evaluation.

Through combining the two graphs, I am curious why Twitter is considered for one-way learning, e.g., teaching, remembering, and understanding, rather than two-way communication. And due to the limit of 140 characters (I guess), Twitter is not considered to be highly used for evaluation as Facebook and YouTube.