Kieran Johnson proposes creating a social media platform called "The Grid" targeting politically left-wing 16-24 year olds. The platform would use multiple mediums like social media sites, a website, and graphics to promote a safe online space for people to discuss topics of interest. Over 7 weeks, the project would develop a visual identity, choose a theme, create content like articles and podcasts, launch social media communities, evaluate feedback, and publish the full platform. The goal is to build a niche community similar to Reddit and Buzzfeed that excels at catering to the interests of its target demographic.