1. When you're in the app, you'll see a little orange indicator on the scoreboard screen. This is your cue that one is available. When you select it, you're taken to live video of whatever Look-In MLB has deemed worthy. This is usually a tense situation, the end of a game, etc. The video plays, live, without blackout restriction, for as long as the tense situation lasts. Pretty damn awesome feature, actually! It isn't restricted to your favorite team or anything like that, either. Could be a dozen in a day of baseball, maybe more.
2. Yup, sure do. Today is White Sox vs. Jays. This is subject to blackout restrictions, unlike the Look-Ins.
3. There are a few bugs. Occasionally buttons will disappear, the "gameday" portion will stop updating correctly, etc. They're all very minor, and they're all almost always solved by a long tap / close on the "running" application. The app is more stable than it has ever been, and is consistently updated throughout the season.