"Claim Your 31st Right," declares the #My31 app's splash screen. "Review, share, and confirm your HUMAN right to your data as your property." (The United Nations Declaration of Human Rights has 30, so a right to data would presumably come next.)
That's why #My31 doesn't bill itself as a business so much as a cause. "Join the movement by staking a claim to data you've produced, declaring it your personal property," proclaims the App Store description. Sign up, the app says, and "get a title of ownership for your personal data". The idea is that once you own your data, you can sell it.