Amazon has pulled the plug on its affiliate program in Colorado thanks to a new state regulation on sales tax collection. The company sent a notice to its Colorado-based affiliates Monday morning to let them know about the decision, urging residents who depend on the affiliate program to contact their lawmakers if they want the program back.

Most states only require retailers to collect sales tax if they have a sufficient enough brick-and-mortar presence thanks to a 1992 Supreme Court decision on Quill Corp. v. North Dakota. Despite this, a handful of states have tried to pass laws in recent years (often dubbed the "Amazon Tax") that would force Amazon to start collecting sales tax if their affiliates—that is, those who use Amazon's affiliate links on their own sites or blogs in order to earn a return on referrals—are based in those states.

Valve has stopped with the teasing and has officially announced that its online gaming service Steam is coming to the Mac. As a bonus, the company also plans to make the Mac a "tier-1" platform, promising simultaneous release of games on Mac OS X, Windows, and Xbox 360.

Valve has developed a Mac-native version of its Source engine, using the cross-platform OpenGL. "We looked at a variety of methods to get our games onto the Mac and in the end decided to go with native versions rather than emulation," John Cook, Director of Steam Development, said in a statement. "The inclusion of WebKit into Steam, and of OpenGL into Source gives us a lot of flexibility in how we move these technologies forward."

Beginning in April, Mac users will be able to access games via Steam, including Left 4 Dead 2, Team Fortress 2, Counter-Strike, Portal, and the Half-Life series. The Mac Steam client is based on the latest version for Windows that is currently in beta, which is where the first hints of Mac OS X compatibility were discovered.

That version includes a new Steam Play API that will allow users to access and play games from either a Windows PC or a Mac. Progress on one platform is automatically updated and synced when using the other, meaning all the fragging you do on your work PC (on your lunch break, of course) will be reflected when you log in from your Mac at home. Playing games on either platform won't cost extra.

The Mac compatibility extends beyond Steam Play, however. All future games, beginning with Portal 2, will be available for the Mac the same day as the Windows version. "We are treating the Mac as a tier-1 platform so all of our future games will release simultaneously on Windows, Mac, and the Xbox 360," Cook said. Players on all platforms will be able to play each other in online multiplayer setups, as well. "We fully support a heterogeneous mix of servers and clients."

These announcements are surely music to Mac gamers' ears. Besides Steam and Valve's own titles, making Source cross-platform also means other developers using Valve's engine can easily create Mac-compatible versions of games without much additional effort.

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Two weeks ago,  that Internet search giant Google had acquired third-party iPhone mail application reMail. At the time, Google rehired reMail CEO and programmer Gabor Cselle to work as a product manager on the Gmail team. reMail was then pulled from the App Store and Google decided to discontinue the app, only offering support through the end of March. However, Google recently contacted Ars to say that it had decided to make the code available as open source on Google Code under the Apache 2.0 License.

The states that the code is free to use, alter, and redistribute as the user sees fit. Further, users can charge for any aspect of the software they choose, including the application itself or support. That means people can use portions of code to add functionality in their own applications or create totally new ones without having to release them under an open source license. Google over alternatives and uses it for Android.

This may still mean the end of reMail, but it's good news for anyone looking to incorporate more advanced e-mail functionality into their own applications. As Cselle pointed out in his , he has already dealt with many of the obstacles associated with developing an e-mail client, including communication with IMAP and parsing MIME messages. In other words, there's no need to reinvent the wheel if you don't have to.

If you're interested in poking around, the code can be found on , where there has already been a fair amount of action since the announcement on Friday.

"The best camera is the one you have with you" is an old photography adage, and Apple may be looking to extend that principle to its iPhone. And it's not about the iPhone as a camera, either—if you always have it with you, an iPhone could serve as a remote control device for any number of uses, including as a wireless electronic key.

Using the iPhone as an electronic key is part of a recently published patent application titled "Motion Based Input Selection." It's important to remember that the patent application itself merely describes a unique way of using motion detection to generate an input, such as turning a virtual combination lock-style dial. Still, it's the suggested uses of a unique numerical sequence or other combination of input that is generating excitement.

The Telegraph says that the patent is already being , based on the suggestion that a "device" such as an iPhone could use the motion-based input method to generate a combination which is then "transmitted to an external device to unlock the external device." Such an external device could be anything, including an "electronic lock that may be used to access a door, car, house, or other physical area."

The patent in particular describes methods in which the input could be selecting combinations of numbers, letters, colors, or images, or even a combination. In fact, if the external device is suitably capable, it can send an application the necessary configuration of input needed to unlock it. The possible inputs can also be randomized, and the transmission between the mobile device and the external device could encrypted for greater security.

Since the iPhone is the kind of device you tend to always have with you, it could be a great all-in-one control device. For instance, Apple also recently filed a patent application for using the iPhone as a sort of —one that can dim the lights, adjust the surround sound, switch the TV to "cinema mode," all in preparation for watching a movie at night. The company already offers an app that can control iTunes or an Apple TV remotely, and other apps exist to control home automation systems or a DSLR tethered to a WiFi-equipped computer. Car security firm Viper also offers an app to lock, unlock, and remotely start a vehicle that has the company's .

Though many remote applications already exist for the iPhone—including one that locks and unlocks a car—perhaps Apple could leverage the patent's motion sensing to build an app with a consistent interface that is designed to communicate with a wide variety of lock devices, making the iPhone an out-of-the-box electronic key.

In an announcement published last week, Nokia's Valtteri Halla revealed that Intel and Nokia are planning to launch the public MeeGo source code repository by the end of the month.

The MeeGo project began to take shape last month when Intel and Nokia announced plans to merge their respective Linux-based mobile computing platforms into a single open source software project. The unified software platform, which consists of technology from Maemo and Moblin, will be designed for use on a wide range of device form factors and will support both ARM and x86 architectures.

Those playing Assassin's Creed 2 on the PC got a rude reminder of DRM's pitfalls when the servers that authenticate the game went down. Many complained on the company's official forum, and tempers ran hot. Remember: the game has to be in contact with Ubisoft's servers to work; if the connection is lost, the game shuts down.

Ars Technica contacted Ubisoft to ask about the issue, and we were told that the issue wasn't simply a server malfunction. "This 'failure' was due to a massive DDoS attack on our servers," an Ubisoft spokesperson told Ars. "Our servers didn't go down but 5 percent of the overall people attempting to connect received denial of service errors. This is, of course, unacceptable and our teams are working around the clock to ensure it doesn't happen again."

The issue of pirates playing the game also gets short shrift. "Neither Assassin's Creed II nor Silent Hunter 5 are cracked at the time we speak. As mentioned previously, 'cracked' versions are incomplete... as in missing whole parts of the game and crucial features," the spokesperson continued. That means that with just the data from the disc or your download, you won't be able to play the game. The content requires whatever the Ubisoft servers are giving it. 

Ubisoft leaves us all with a reminder that no matter how intrusive or failure-prone it is, DRM isn't going away. "We worry about our customers and apologize to anyone who couldn’t play ACII or SH5 yesterday. All in all, we hope people understand all this is done to preserve the future of PC gaming."

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