I see it also, I'm in the top 5 and am rarely on the front page. It has more to do with lucky timing than anything. There are a lot of memes featured every day, even a good spot on the latest list only lasts an hour. It helps to have a following true, even so if nobody else is around to see it you will get those upvotes then nothing. I believe it is simply a matter of having the type of meme people want in a good spot so they can find it. A tricky combination, but one that is random and doesn't favor anybody over another. I can spend hours photo shopping something only to have it get buried. While a meme I simply put a caption to a picture gets a good spot and makes front page. No rhyme or reason it's just how it is, I try to find new users with good stuff it's just more fun that way ;)