Well, if they based it solely on favs, some people would get their workplace or all their friends on FB to fav their lolz despite the quality. Not exactly fair to others. We want to see the best lolz on the FP, not just the most popular. If only good lolz make the voting page, that promotes quality.
Last time I heard, they sort through some 7000+ submissions daily. Favoritings may have some impact, but not always. I've had lolz picked that had no favs and lolz that had 15+ favs that didn't get picked. From what it looks like to me, they look for the best lolz so it forces people not to submit crap. It has improved the quality of the FPs considerably over the old voting system.
I have found that you can vote from the vote section and to get there, you've got to get cheez peeps to favorite your lolz. That's what the powerz that be at icanhascheezburger.com told me in an email response. I'm favoriting some of yours cuz I like them.
wweel da teacher toldss us we hadd a quis yesterday. we studied. got to skewl and fwigured out she waz april foolin us >.< & now all da seniors r on fwield trip so nwos thurs vury little pweople in all my classes. & skewls going by sloww. :/ longg day ahead.