Honestly as I have experience on this kind of ideas, first you need to do the product itself(must be unique, if there is nothing new, community will just snob it), next, market it(for people to actually like it), but as I told, if its unique and enjoyable, it can market itself easily. Then third, retain it properly, hire professionals on maintenance, bug fixes. Like that.
The thing to consider, if you will really make it, You need at least 100BTC for it be successful. You need it for bankroll, for the steps i listed above., and more importantly the license of your made site. depends on the country or jurisdiction you are living in.