I believe Path is what you are referring to with the emoticons. That was the first feature of Path that I found really innovative - it encourages greater participation because it's faster than commenting, like the "Like" button, but allows you to convey a greater degree of emotion. But I still comment on photos in Path - having real conversations are valuable in most situations.

Hard to answer for your particular site without knowing more detail, but why not just use Disqus? They're likely to be better than what you hack together yourself, and most early adopter types are familiar with it which will probably increase your engagement rate.