(This UI Guide is based on version 1.2.4 in iPhone.)
1. Home Folder
1) Sync button: Start sync manually or stop sync while syncing.
2) Sync status bar: Last sync date info.
While syncing, display current process in detail. When just finished sync, show last sync result.
3) Edit button: Change the order of folder list or remove user added folder. Adding folder to home can be done by folder action menu.
4) Article count: Recent day’s unread/read count and total count. Recent day interval can be changable by user at ‘unread counting’ item in display setting menu.
2. Article List
1) Grouping button: Available grouping options are by feed, label, google attribute(starred..), tag, author, and date. some options(tag) are recursive.
2) Filtering button: Filter out current folders article by read/unread, facebook like count…
3) Swipe right: Same effect as back button(going to parent folder).
4) Long pressing cell: When long pressing cell, article action menu will pop up. ‘Mark all as read older than this article’ menu will appear only in this popup.
Additional,Title tapping: Shortcut to parent folder path and recently viewed article list will popup.
3. Article View
1) Swiping Left/Right: Go to next/previous article. Same effect as next/previous button in navigation bar.
2) Double tap: Double tapping in content area will toggle visibility of navigation bar and toolbar. When user made first scroll, bar will be automatically hidden.
3) Social bar: You can enable/disable this social bar in social setting menu.
4) Long press menu: When long pressing content words, additional menu appear.
Wikipedia, Google, Wiktionary and Search in article is provided default. You change the order and visibility of menu at display setting.
And two more ‘user defined menu’ are available. With user defined menu, you can add some localized dictionary for your language.
RssBook 
Any plans to increase font size? Max works out to be a 7 or 8 pt.
Which UI interface you mean? For article view, there’s already ‘font size’ setting in toolbar. Is it not enough for you? Please let me know a more detail of question.
Is there a way to delete the articles I’ve read. I see that you can filter them but I want to remove them from my iPad entirely.
Hi, ed.
As you pointed, there is no way to delete specific articles only. We expect similar effect by changing folder’s filter setting to unread only. It will automatically hide read articles in that folder. (And folder’s filter setting is also saved when changed. so, next time, you access that folder,it will display unread article only!)
BTW, RssBook is highly optimized and specialized for accommodating large articles. It does not load all the articles data. It load just index only. In fact, number of articles does not matter for most case.