Founder here! Keep in mind that we provide laundry, utilities, and shared kitchen and bathroom supplies. We also host a lot of dinners and shared events / meals / etc for the community.
Lots of things - mostly that we have the entire buildings rather than single units, which is particularly important in NYC where we're operating right now.
We also partner with real estate funds and investors to purchase vacant buildings rather than leasing units off the market.
No - subletting / listing a bedroom on Airbnb at Common isn't allowed. It's a pretty tight community of 19 people so your roommates would definitely notice.
The post is focused on 20-somethings who want to live in an urban area. Manhattan is somewhat analogous to San Francisco; it tends to have a high concentration of young people who want to work in tech and startups.
It's also month-to-month and furnished.