Also there is another aspect to cardsets that might be worth thinking about, which is that they are like "polling" done in a fun and easy way (swiping on pictures) -- the fact that you can also show people that answered similar to me doesn't need to be the focus.

Having polls like this can help you grow the site. For example, imagine I make a cardset for "Beatles albums" where I put in each Beatles album, and shoot the link out to, say, r/Beatles or whatever. Your site can let people swipe, then show the aggregate % for each of the cards, thus ranking them.

Of course... having viewed this really fun and quick poll, random pollers might wish to make their own new polls and spread your site.

Enjoy your sleep.. you have a long journey ahead of you!