Final answer:
Howard falls under the category of Spectators in social media participation, as he consumes content like blogs and videos without creating or sharing content himself.
Step-by-step explanation:
The category of social media participant that Howard falls into is D. Spectators. Spectators are those individuals who do not actively create or share content but are interested in consuming the content created by others. This includes reading blogs, listening to podcasts, watching videos, and generally engaging with material produced by others without actively participating in content creation or discussion.
Spectators make up a large portion of social media users and are an important part of the ecosystem as they drive views, reads, and indirectly influence the popularity and dissemination of content through their engagement metrics.