Dapponline.io is using the API access provided by Steem Apps, which is exactly what I've been thinking about when designing & developing it - making it as easy as possible for 3rd-party sites to be able to list/add Steem.
If you have a twitter account, please head over to their profile and show them some love.
We Are Steem!
All the best,
Do you believe that my work is valuable for Steem? Then please vote for me as witness.