Linkedin, Mint, and Yelp are somewhat different. Email is part of their communication with users. Groupon and the other email companies use email as their prima

Linkedin, Mint, and Yelp are somewhat different. Email is part of their communication with users. Groupon and the other email companies use email as their primary service. They curate information and deliver it to their readers. I have been thinking about doing something in this space, but after some initial customer development decided to give up on it.