No focus on content area
Open new tab, go to theoldreader, click one of the feeds.
After that pressing Up/Down arrows on keybord will scroll the feeds list, not the feed content, you need to click in content area to focus it.
I know about J and K hotkeys, but arrows are kind of native thing for navigation.
BTW Google Reader somehow does the focus of content area :)
Eric U. commented
Yup. I use a bookmark that points to http://theoldreader.com/posts/all; after going there, I still need to click in the feed content to get the arrow keys to work. One call to setFocus would fix this.