I'm sure there are many people like me: the reader seems to have 1000+ unread forever! And I think the fact is: this is a world, that you just can't read over!
Comparing have to unsubscribe something, I prefer to subscribe all seems to be interested, with no care of the quantity.
We all know that Google has the best codes to determine the order of search results, why not to use that for sorting unreads in Reader?
Change the mind to forcing users to read all, but to smart sort the unreads according to their likes. I think this is a better way of reading.