I really like the app so far! Great work! I did find a couple bugs though:
1) You probably shouldn't use the same bar to split the article and comments that Windows uses to resize pinned applications. This makes it look resizable when it's not.
2) Sometimes my mouse's scroll wheel stops scrolling. I think this has something to do with the ad reloading. I don't know if you have any control over that, but I found it annoying. I think the ad is stealing focus.
3) The ad on the main page stays on top of the Settings flyout (Win+I -> Settings)
4) Right-clicking on the article side (the web control) causes the appbar to fly in and then immediately disappear. The article also flickers. This does not repro when right-clicking on the comment side.
Most of these are ad related, so maybe that's my cue to buy it... Otherwise, great app! I like it.