Next up on my list, fixing the checkboxes interface in the timeline .
Checkboxes is a dialog in the timeline that lists all the feeds this timeline contains. All boxes are checked by default. You can hide a feed's items by unchecking the box. This does not affect your subscription, just whether the items are visible. You'd want to do this for a linkblog feed, where you might post twenty links in a day, but other sites you're likely to post far fewer.
What needs fixing. I simplified how this works, and this part of the UI has yet to catch up.