Click on any of the images below to launch the image player. Virtual Post-Its
With new software developed at Siemens Corporate Technology in Munich, users of Global Positioning System-equipped cell phones and handheld computers may soon be able to leave each other virtual post-it notes.

The Siemens system could do everything from helping highway department personnel label pothole locations for road crews to allowing a city's residents to craft personalized guides for visiting friends. A user of the software can leave a note in a particular location by sending a message from that spot on his or her wireless device. The system transmits the message, along with the GPS coordinates of the location, to a server. When the intended recipient (who must also have a GPS-enabled wireless device) comes within a preset radius of those cordinates, the server delivers the message. Siemens expects to license or commercialize the technology in about two years.

Touchy-Feely Screen
Touch screens greet tourists at museums, shoppers at checkouts, and even drivers on dashboards. In spite of the name "touch," though, they don't feel like much--just flat, boring glass or plastic.

But press a virtual button on a screen from San Jose, CA's Immersion, and you'll feel the same satisfying clack you'd feel pushing a key on a keyboard. The device works by tricking your sense of touch. Precise motors vibrate the top layer of the display. The vibration varies depending on which graphic you touch--a car's thermostat, say, or its radio tuner--creating a distinct sensation for each. An on-screen visual response and an audible click or buzz add to an illusion that overrides your perception of the display's hard surface. Immersion is currently licensing the technology and shipping demonstration models to automakers, display manufacturers, and other companies.

Low-Power Data
Some gadget lovers read the news on the fly using small displays such as watches equipped with Microsoft's Smart Personal Object Technology (SPOT). But the devices, which pick up wireless "datacasts" with updates on traffic, stocks, sports, and the like, must be recharged every couple of days--which limits their appeal to mainstream consumers.

Now a battery-sparing innovation could enable datacast receivers to go longer between charges. Pablo Rodriguez of Microsoft Research and Julian Chesterfield of the University of Cambridge realized that if some of the information in a datacast is unchanged from the previous download--say, for instance, it's still 35 degrees and sunny--it's a waste of power to download it again. They created a system that precedes each update with a highly compressed signature or "hash" of each of its components. If a device finds data with a matching hash in its memory, it doesn't bother to download that component. In experiments, the system reduced download times by 40 percent--meaning wireless watches would use less juice.

Fail-Proof Focus
Tired of blurry photographs? Ren Ng, a computer science graduate student at Stanford University, has developed a digital camera and software that allow photographers to refocus images after they have been taken.

The trick lies in a 296-by-296 array of 125-micrometer-wide lenses placed between the main lens of the camera and the image sensor. In effect, the array divides incoming light from a single shot into multiple images--each captured from a slightly different angle--that are all recorded at the same time by different regions of the camera's image sensor. Software then allows the user to digitally refocus the resulting image at different depths--to pick up a person otherwise lost in the background, for instance.

The limitation of the technique is that the refocused images are relatively low resolution, since the pixels of the camera's image sensor are divvied up to register multiple perspectives. While this is currently a barrier to widespread commercialization, Ng expects refocusability to be the next killer app in photography, as cameras' pixel density continues to increase.

Music Dial Tone
Venture capitalist Fred Wilson cofounded Flatiron Partners, one of the spark plugs for New York's late-1990s "Silicon Alley." Now a partner in Union Square Ventures, he blogs on venture capital and new media.

How do you see the future of music shaping up?
All the pieces are basically there for what I call "music dial tone." Once it's all together, for less than $5 a month, you'll have access to the entire library of recorded music, from any place and any time. By the end of this decade, it will be the dominant way people consume music.

What's the revolution?
The revolution is the business model. Most telecom services now charge a flat fee per month. When music goes this way too, consumers will start to expect all media to be delivered this way. TV and film--other than first-run movies in the theaters--will be next.

You've got an investment in high-definition radio--why will anyone want that?
My iPod has been an eye-opening experience. I have thousands of songs on it, but I am listening mostly to podcasts [homemade, downloadable, MP3-format radio programs]. Why? Because I want someone to program my iPod. When we have music dial tone, we will still want someone to program it for us. That's what radio does. Radio execs already understand this. They just need us to build the digital platform--and by that I mean music dial tone--and they'll provide the programming and monetize it. -- By Spencer Reiss

Copyright Technology Review 2005.