Comparing smartphone operating systems

Apple's announcement of iOS 4 and the iPhone 4 in just the last three months shows that the smartphone wars aren't cooling yet. Just consider everything that has happened in the space of the last year. Microsoft's Windows Phone 7 is a top-to-bottom overhaul of the Windows Mobile OS, and Google continues to aggressively roll out updates to Android. Palm hasn't been quite as active in the news recently, but we're not discounting its WebOS quite yet.
The following chart compares popular features from the smartphone operating system that have been most active this year. Note that we left RIM off because the manufacturer has not issued major updates in the past 12 months. A quick look at the chart demonstrates just how competitive the OS battle has become. As each company fires a shot, you can expect its competitors to respond in force. And that's something we love to watch.

	Apple iOS 4	Google Android 2.2	Palm WebOS 1.4	Windows Phone 7
Consumer availability	June 21	TBD; will vary by device and carrier	Now	Fourth quarter of this year
Multitasking	Yes, but iPhone 3GS and iPhone 4 only	Yes	Yes	Yes, but limited. Third-party apps will not be allowed to run in the background.
Notifications	Yes, but only one at a time	Yes, with multiple notifications bar	Yes	Yes
App folders	Yes	Yes	No	Apps arranged in "Hubs"
Tethering	Yes	Yes, with built-in support for tethering and mobile hotspot feature	Yes, but dependent on carrier	TBD*
VoIP	Yes, with third-party apps	Yes, with third-party apps	Yes, with third-party apps	TBD
Gaming	Many gaming apps available. Game Center feature adds new functionality	Many gaming apps available	Palm publicly released its PDK in March for game development. 3D games are already available.	Xbox Live integration
Flash support	You're kidding, right?	Yes	Yes	Yes, but not at launch
Number of titles in App Store	iTunes App Store: More than 225,000	Android Market: More than 30,000	Palm App Catalog; More than 2,400	Windows Phone Marketplace; hasn't launched yet
Voice commands	Yes	Yes	No	TBD
Mass storage	No	Yes	Yes	TBD
Universal search	Yes	Yes	Yes	Yes
Music store	iTunes Music Store	Amazon MP3 Store	Amazon MP3 Store	Zune
Web browser	Safari	Android	WebKit	Internet Explorer
Copy-paste	Yes	Yes	Yes	No
Pinch and zoom multitouch	Yes	Yes	Yes	Yes
Video calling	Yes, but iPhone 4 only	Yes, but on limited phones	No	Not yet

* Microsoft has yet to fully detail the features for Windows Phone 7.

Editors' note, Monday, April 12, 2010:  This chart was updated to show that Palm WebOS 1.4 supports third-party VoIP applications. This chart was further updated on June 14, 2010, to reflect the changes from iPhone 4 and Android 2.2

Source here