Now, you can comment. A user can leave comments on a card after that user buys that card. Your choice to leave a comment or not. I never leave a comment, but I still read them before buying.
When you want to switch pages from one card to another, just click the bar to the right of the names of the girl and card. Clicking that will bring up the same list as you saw before. This time, there will be two separate lists of cards. Those that are in your collection (you bought them or got them with your subscription) are listed first. After that list comes the cards not in your collection.