In Feedback you can check favorite list. Mine has over 100 entries. But only the top five in my priority list count for the ranking. And in that top 5, the first entry gets more points than the fifth entry. So I have to put my number one bug fix request on the top.
Looking again on the top 20, there must be something like hundreds of people who have the iPhone support request on their top 5. But why? I think Geoff told that they plan to support iPhone as soon as possible, so supporting that request is a waste of your ranking points.
And remember, anything that you don't put in the top 5, is not important for you.