* The "queue" design closely matches my use of Google Reader: skim through new items, opening anything interesting in a tab.
* The design is simple, readable & reasonably attractive (except the text shadow on headlines, but that's just my taste).
* Lightboxing of articles is clever & useful.
* I like the behavior of expanding articles in list view better than Google Reader's behavior.
And some bad:
* I can scroll the whole UI up & down by a few pixels. (http://i.imgur.com/LIjQf.png)
* Firefox Aurora takes about a second to switch to the FlowFS tab if it's been in the background for a while. Not sure if this is your bug.
* The "show more" button seems to either fail silently or take an unreasonable amount of time to load. Some visual loading indicator would be nice.
* There's a bug when closing an expanded list-view item. (http://i.imgur.com/UErc8.png)
* I'm not sure how you're going to make money.