The on the support page states that it «allows you to automatically pair bitcoin transfers to or from your Coinbase Account with corresponding bitcoin purchase or sale transactions». (coinfox.info)
You can contact other members for free as their home page states however you will need to upgrade to a paid membership to read any messages that you receive. (bestdatingsites.com)
There is nothing on the application page stating the bonus miles. (flyertalk.com)