It really is, for most of us at least. You can comment all you want really. However meaningful comments are always better than something generic like a random "LOL" or what not. Just be social really. :)
Well it's nice of you to say that, but I think in most cases, a "top" user's memes are not necessarily better than every other user's (though some top users make good memes).
Overall, it's a lot more about how much time you spend on the site, and your activity level on here. If you comment more, and stay active, you get points for that, plus it makes it more likely that people will look at your stuff.