Last Updated Jun 22, 2010 9:06 AM EDT
Dave already talked about iOS 4's business productivity perks. But let's look beyond tent-pole improvements like multitasking and folders to some of iOS 4's lesser-known tweaks -- and how they'll improve your iPhone life.
1. Background tasks Not to be confused with multitasking, "persistent backgrounding" allows apps to continue performing certain operations even when they're not in the foreground. For example, your GPS app can continue providing directions while you're talking on the phone. And an app like Line2 (which effectively gives you a second phone line) will be able to accept incoming calls even when you're not viewing it. That's huge!
2. Geolocation iOS4 lets you sort your snapshots by location and see them on a map. It's way cooler than it sounds, and I'm especially impressed that it works with photos I've already taken. This is fantastic for folks who travel a lot and/or need to know where they snapped particular shots. (Realtors in particular will go nuts for this.)
3. iBooks I know, I know, we already have eReader, the Kindle app, Stanza, etc. But it just wasn't fair that only iPad owners got to have access to Apple's long-overdue e-books and e-bookstore. The latter has nowhere near the selection of the Kindle store, but that's sure to change. (By the way, what's "hidden" about iBooks is that it doesn't come with the OS -- you have to download it from the App Store.)
4. Orientation lock Tired of the screen rotating when you don't want it to? Now you can activate a soft-lock (though only for portrait mode). Just double-tap to bring up the app selector, swipe to the right until you can't go any further, and then tap the gray orientation-lock icon.
5. Over-the-air note syncing As you may have discovered, the Notes app now has an Accounts button. If you're currently using any IMAP-based e-mail account(s), Notes can sync with that account. In the case of Gmail, you get a new "Notes" label on the Web side. With other IMAP accounts, you'll see "Notes" folders. Wonky, but it works.
What lesser-known iOS 4 features are you liking? Is there anything about the OS you don't like?