I don\'t think either of those possibilities have stopped people replying.
First of all, you started a small contest, which made people forget about comments/critiqu? and just want to guess the caption.
Secondly, not that many people come to comment on artwork unless they just want to post \"WOW that\'s awesome!!1\". Once you\'ve had the initial wave, you can\'t expect people to carry on commenting with the same enthusiasm that they had when you, a great new artist, and your work, came along.
Finally it\'s possible that people require something new (a new style, new way of colouring, shading, etc) after a while. Simply put, they may just be bored. (But that\'s far from saying your artwork is \'boring\' in its own right- I hope you understand what I mean).