Editor's note: This story is part of a series we call Redux, where we'll re-publish some of our best posts of 2009. As we look back at the year - and ahead to what next year holds - we think these are the stories that deserve a second glance. It's not just a best-of list, it's also a collection of posts that examine the fundamental issues that continue to shape the Web. We hope you enjoy reading them again and we look forward to bringing you more Web products and trends analysis in 2010. Happy holidays from Team ReadWriteWeb!

Sixth Sense: Sixth Sense is an extremely inexpensive interface ($350 to build the prototype) and it consists of some colored finger markers, a projector, and a camera on a necklace. Demoed at the TED conference, this interface has amazing potential. We reviewed this product as part of our post The Wearable Internet Will Blow Mobile Phones Away.

Given Nikon's release of yesterday's first camera with a built-in pico projector and Mobileburn's demo of the Samsung Anycall Show phone, these little projectors are about to start popping up everywhere. For Minority Report fans, we may actually see these projector based interfaces used up for everyday tasks; however, it's more produce amazing entertainment for gamers.

Perceptive Pixel Multi-Touch Wall (Jeff Han's new project) and Microsoft Surface: In the world of alternative interfaces, these two workstations are extremely well known. Certainly not the inexpensive, mainstream touch interfaces we'd hoped for, their size and price makes them unobtainable to the average user. However, for commercial uses, they've certainly got that wow factor. The products are used for story boarding, geo-spatial command, broadcast media, museum exhibits, hotels and Surface is even in Disneyland's tomorrow land.

Scratch Input: Recently featured in Technology Review for his presentation at the SIGGRAPH Conference, Carnegie Mellon Ph.D student Chris Harrison created a gestural input interface using existing surfaces and an acoustic input technique. In other words, Harrison's interface uses scratches to communicate with his machine. By taping a modified stethoscope to a wall, Harrison got users to perform six scratch input gestures at about 90% accuracy with less than 5 minutes of training. If Scratch Input were utilized by a mobile manufacturer, a phone owner could simply rest their device on a table top and use it to scribble out messages.

Pulp-Based Computing: While there's little information on these projects just yet, one thing is clear. The folks in MIT's Media Lab Fluid Interfaces Group are exploring electrically active inks and fibers during the paper making process to create a new form of paper-based computing. Apparently the paper would react in the same way as regular paper; however, it would also carry digital information. While the project is only in its early stages and appears to be hooked up to a basic Arduino prototyping platform, theoretically this could be used to create a new type of Wacom tablet. Remember when Steven Levy wrote about losing his Macbook Air? A paper interface would take some serious getting used to.

Siftables: Created by David Merrill and Jeevan Kalanithi, Siftables is a series of blocks that contain built-in motion sensors, graphical displays and wireless communication. The blocks can be programmed to interact with digital information and media to form a collective interface. Siftables have been used to create art displays, painting tools, calculators, games and even a music sequencer. Bug Labs also offers a similar open source block system for modular device interfaces.

For more on alternative interfaces featured during 2009, check out our articles on the BiDi screen and the wearable Internet.

Sixth Sense: Sixth Sense is an extremely inexpensive interface ($350 to build the prototype) and it consists of some colored finger markers, a projector, and a camera on a necklace. Demoed at the TED conference, this interface has amazing potential. We reviewed this product as part of our post The Wearable Internet Will Blow Mobile Phones Away.

Given Nikon's release of yesterday's first camera with a built-in pico projector and Mobileburn's demo of the Samsung Anycall Show phone, these little projectors are about to start popping up everywhere. For Minority Report fans, we may actually see these projector based interfaces used up for everyday tasks; however, it's more produce amazing entertainment for gamers.

Perceptive Pixel Multi-Touch Wall (Jeff Han's new project) and Microsoft Surface: In the world of alternative interfaces, these two workstations are extremely well known. Certainly not the inexpensive, mainstream touch interfaces we'd hoped for, their size and price makes them unobtainable to the average user. However, for commercial uses, they've certainly got that wow factor. The products are used for story boarding, geo-spatial command, broadcast media, museum exhibits, hotels and Surface is even in Disneyland's tomorrow land.

Scratch Input: Recently featured in Technology Review for his presentation at the SIGGRAPH Conference, Carnegie Mellon Ph.D student Chris Harrison created a gestural input interface using existing surfaces and an acoustic input technique. In other words, Harrison's interface uses scratches to communicate with his machine. By taping a modified stethoscope to a wall, Harrison got users to perform six scratch input gestures at about 90% accuracy with less than 5 minutes of training. If Scratch Input were utilized by a mobile manufacturer, a phone owner could simply rest their device on a table top and use it to scribble out messages.

Pulp-Based Computing: While there's little information on these projects just yet, one thing is clear. The folks in MIT's Media Lab Fluid Interfaces Group are exploring electrically active inks and fibers during the paper making process to create a new form of paper-based computing. Apparently the paper would react in the same way as regular paper; however, it would also carry digital information. While the project is only in its early stages and appears to be hooked up to a basic Arduino prototyping platform, theoretically this could be used to create a new type of Wacom tablet. Remember when Steven Levy wrote about losing his Macbook Air? A paper interface would take some serious getting used to.

Siftables: Created by David Merrill and Jeevan Kalanithi, Siftables is a series of blocks that contain built-in motion sensors, graphical displays and wireless communication. The blocks can be programmed to interact with digital information and media to form a collective interface. Siftables have been used to create art displays, painting tools, calculators, games and even a music sequencer. Bug Labs also offers a similar open source block system for modular device interfaces.

For more on alternative interfaces featured during 2009, check out our articles on the BiDi screen and the wearable internet.

According to Newsweek, both the iPod Touch and to a lesser degree the iPhone are increasingly being used by the U.S. military because of their versatility, ease of use and comparative low cost.

Software developers and the U.S. Department of Defense are busy developing military software for iPods in an attempt to gives soldiers even more functionality. A new program called Vcommunicator produces spoken and written translations of Arabic, Kurdish and two Afghan languages.

"Snipers in Iraq and Afghanistan now use a "ballistics calculator" called BulletFlight, made by the Florida firm Knight's Armament for the iPod Touch and iPhone. Army researchers are developing applications to turn an iPod into a remote control for a bomb-disposal robot (tilting the iPod steers the robot). In Sudan, American military observers are using iPods to learn the appropriate etiquette for interacting with tribal leaders," the report says.

According to an Army official in Baghdad, the devices have yet to be successfully hacked and at $230 a pop, the iPod may fit right into President Obama's 663.7 billion dollar defense budget.

Plastic Logic's Reader

The first product on our list is Plastic Logic's upcoming e-book reader. A demonstration of this device at the past DEMO08 conference left many people amazed at how incredibly thin this potential "Kindle-killer" is. The company says they've perfected a way of printing polymer transistors onto flexible plastic displays. This particular revolution won't be just a transition to lighter and "bendier" touchscreens, it will also lead to lower power consumption and longer battery life.

But perhaps what's best about Plastic Logic's technology is the cost. The polymer-based circuitry will be able to bring new products into market where silicon microchips were simply too expensive. Since the displays are flexible enough to be rolled up like paper, the potential for this new type of computing is nearly limitless. Is this the future of the newspaper? Perhaps, but it could also be used in smart electronic tags that track merchandise and large flat-panel displays.

Plastic Logic will begin their entry into the market in the second half of 2009 with pilots and trials with key partners and will prepare for further sales by 2010.

Pressure-Sensitive Computing: Impress

For an inventive, "out-there" product that could make the cold, stiff computer a thing of the past, look no further than this touch screen flexible display called "Impress" (PDF). Made of foam and force sensors, Impress works with both touch and the intensity of pressure. This computing technology lets the user squeeze out information or put objects in motion by deforming the surface of the computer.

The end result is pretty amazing, though it may not end up being as practical as the flexible polymer displays. However, it's easy to imagine how it could be put to use in entertainment-based computing at the very least. (Or maybe huggable, touch-enabled teddy bears? We can only hope!)

The Touch OS: Windows 7

While its easy to see the usefulness of touchable handheld devices, others have questioned how exactly touchscreen computers - such as the upcoming Windows 7 OS - would be useful to consumers. Suggestions have included everything from control panels for the smart home to kitchen PCs for touch-based recipe look up to touchscreen Media Centers. However, the answer as to what could really impact touchscreen PC adoption may be as simple as this: games.

At this year's CES, a demo of a Windows 7 air hockey game demonstrated the potential for a new type of human-computer interaction...like an iPhone but much, much bigger.

In addition, Microsoft also introduced two new Surface applications for Windows 7 at CES as well. One that allowed for photo manipulation and another for interacting with maps.

Yet there still is a question as to whether the iPhone-like multi-touch capabilities of a touchscreen OS will become as big of a hit in traditional computing as they were on the smartphone.

These above examples of touchscreen-based computing demonstrate the new ways we may interact with technology - and therefore the web - in coming years. It's a glimpse into the future of a world where our interactions with technology come more easily and more naturally than ever before. This trend will continue to move computing away from being an activity for technophiles alone and will make it an activity that everyone - even mainstream users - will enjoy.

Disclosure: Sarah Perez also blogs for Microsoft's Channel 10.