So it seems Secret is the new thing. So I had a look at their terms of service. Here are some extracts:
TL;DR: They’re not good.
However, unless we expressly state otherwise, your right to use the Service does not include (i) publicly performing or publicly displaying the Service,
That’s funny, because it seems to imply that taking a screenshot of a secret and tweeting it is forbidden (although the Secret co-founder uses them in his post explaining how it works technically.)
When you post, link or otherwise make available content to the Service, you grant us a nonexclusive, royalty-free, perpetual, irrevocable and fully sublicensable right to use, reproduce, modify, adapt, publish, translate, create derivative works from, distribute, perform and display such content (...)