The idea is interesting.
Will participants know that they are in the project?
Not sure I follow what you mean. Only people that download the app and register will be shown within the app. If you want to matchmake a facebook friend of yours that is not on the app, you can do so and they will be sent a facebook message to go download the app before they can like another single person.
I hope I've answered your question, but let me know otherwise.
A good idea! I will invite friends
I agree with you! I will wait for the release of the application and also invite my.