Josh Ginter in A Roundup of Apps With Great iPad Trackpad Support at The Sweet Setup:

Lastly, because Unread is built around swiping, I’ve found you can process and triage your RSS feeds faster using just two-finger swipes than in any other RSS app available. After drilling into a feed’s article list, marking all the articles as read is as simple as swiping with two-fingers beyond the bottom of the list, revealing a Mark All as Read indicator before sending you to the next feed’s article list.

I encourage you to read the article and check out other apps with great trackpad support.