I'd make accounts 3-tier: 1. anonymous, free, limited use (300 tweets per month) 2. consumer, verified identity, paid, $10/month (1500 tweets per month) 3. com

I'd make accounts 3-tier: 1. anonymous, free, limited use (300 tweets per month) 2. consumer, verified identity, paid, $10/month (1500 tweets per month) 3. commercial, verified identities, paid, $25/month per user (3000 tweets/month) 4. commercial, verified identities, paid, $100/month per user (unlimited tweets)