Moore’s Law states that the number of transistors that manufacturers can put on a single semiconductor chip doubles about every two years. Although it’s really just an observation or a prediction, this “law” has held true for almost 40 years. It’s meant that computer makers can either double the power of their products every couple of years – without raising prices – or squeeze the same amount of computing power into ever-smaller and cheaper packages.

While 2005 was no exception to this trend, what made it unusual was that researchers, software engineers, and entire communities found innovative ways to take advantage of computing’s growing power and falling costs. A few examples: research capitalized on the industry’s better understanding of silicon and how to manipulate its properties; web programming projects made use of computers’ increasing processing speed and networking capabilities; and people worked together to adopt and adapt maturing computing technologies to enhance social life and community.

Here are five stories we think exemplify these exciting and far-reaching themes.

Municipal Wi-Fi

About a year and a half ago, only a handful of municipalities were thinking about providing citywide Wi-Fi access. Now there are more than 300 U.S. cities considering municipal Wi-Fi, which would provide inexpensive wireless Internet access anywhere, for anyone: in a park, library, home, or car.

This year’s most important development in Wi-Fi may turn out be the discovery in October that Google is bidding to fund a network in San Francisco, providing free wireless Internet access to all of its 750,000 residents. Google plans to pay for the project by selling ads that would be served to Wi-Fi users.

Indeed, many big Internet companies see business opportunities in municipal Wi-Fi. EarthLink was chosen to build the wireless infrastructure for Philadelphia – a project that will be especially closely watched, since Philadelphia saw the most publicized clash over who has the right to build municipal wireless networks. Verizon, which runs Philadelphia’s phone system, lobbied hard to keep the city government from building – or even contracting out – its wireless network, arguing that it would disrupt free-market competition. And the state legislature passed a law requiring Pennsylvania municipalities that want to build their own Wi-Fi networks to submit a plan by January 1, 2006, or be forced to get permission from the local phone provider.

Citywide wireless broadband access doesn’t benefit just computer users, but also cell-phones users, a growing number of whom can receive wireless Internet data and can communicate on multiple frequencies, including Wi-Fi, says Dirk Trossen, who studies wireless networking at Nokia. Wi-Fi for phones would be appealing “not only for voice calls but also for citywide services, such as shopping guides,” he says. “This would also enable cities to approach communities or shop owners to help deploy the city Wi-Fi – or at least better argue for the benefits of such engagement.”

Silicon Photonics

It’s safe to say that when a research group publishes three papers in the journal Nature over one year, those researchers are shaping their field. In 2005, Mario Panicia’s group at Intel scored the hat trick, reporting, among other things, that they’ve developed new ways to integrate light into silicon. They created a silicon laser – an advance that could lead to faster processing (photons are less sluggish than electrons), smaller devices, and cheaper lasers, for everything from cancer detection to precision dental work (see “Intel’s Breakthrough,” July).

Most light-emitting semiconductors – those found in a laser pointer, for instance – rely on alloys of gallium and arsenic, materials that are relatively good at transmitting photons, but not so good at shuttling electrons. Silicon, on the other hand, is a first-rate conductor of electrons, while its optical properties have made generating light challenging.

Panicia’s work has shown that, with a few structural modifications, silicon can host photons as well as electrons. “The physics is the same,” says Panicia. “We’ve just used new architecture to manufacture the light.” The work at Intel, as well as other centers of photonics research, is changing the way silicon can be used. The silicon laser was “a major psychological breakthrough,” says Pannicia’s. “No one thought you could do it.”

Social Machines

A new business and advertising model for the Internet emerged this year. Unlike the preceding version, which centered around online stores and services, “Web 2.0,” as it’s often called, has a distinctly social aspect (See Social Machines, August). “This is the year that venture capital started flowing,” says Jesse James Garrett, co-founder of Adaptive Path, a website consultancy in San Francisco. “It certainly has been an interesting year…We saw social software becoming mainstream and we saw a lot of home-spun social software projects being scooped up by big names and being imitated.”

Yahoo, for example, acquired both flickr.com, a web service that allows people to upload photos and label them with “tags” so other users can search particular genres for images, and Delicious, a “social bookmarking” website that lets people note Web pages of interest, tag them in a category, and share them with others.

Moreover, Rupert Murdoch’s News Corp bought myspace.com, a social networking site that allows people to connect to friends, friends of friends, and so on. Though only about two years old, myspace.com has more than 40 million members, who use the site to blog, post descriptions of themselves, and upload music, pictures, and video.

The most popular “social computing” sites are bundling existing technologies, such as blogging software and filesharing, into packages that appeal to the social nature of people. “Having cool technology isn’t enough,” Garrett says. “What you’ve got to do is deliver compelling experiences.”

Search

In the 1990s, searching the sprawling network of Web pages across the Internet was a hit-or-miss endeavor. Then Google arrived with algorithms that ranked pages across the Web according to their popularity (roughly measured by the number of incoming links). In 2005, search technology became much more directed. “Vertical” search – searching within an industry, subject, or activity – is becoming more popular. Technorati.com searches millions of blogs, while IT.com and Become.com offer specialized results to corporate infotech buyers and shoppers, and Google is scanning and indexing library books. Along with competitors Microsoft and Yahoo, Google is also offering local searches, complete with driving directions, user recommendations, and maps that show road, satellite, and aerial views of cities.

This year has also seen the emergence of “anti-algorithm” search methods, which rely on Flickr- and Delicious-style tagging of pictures and websites by users. The movement is also exemplified by Yahoo Answers, which allows users to generate responses to others’ posted questions.

Schuyler Erle, coauthor of Mapping Hacks, believes that the personal touch is important for directed local searches. For example, users might want to know that the top-ranked pizza parlor in Lawrence, Kansas, occupies that position because it’s popular with the locals – not because the owner paid to advertise it prominently. “In order to come up with meaningful search results, you’re probably going to need human intervention to categorize and sift through it all,” Erle says.

Feeds

In December 2005, the Oxford American Dictionary added the word “podcast” to its latest edition. The popularity of podcasts – audio shows distributed to computers and portable music players via the Internet – has made an impression on lexicographers – as it has on popular culture. But the wild success of podcasting has been driven by a technology that’s more fundamental than the audio medium itself: subscription-based “feeds” that allow people to sign up for regularly delivered electronic content, whether it’s a favorite blogger’s latest ruminations or the newest show from a podcasting personality.

Feeds, such as RSS (Really Simple Syndication), are available for news headlines, online calendar changes, video and still images, or anything that’s regularly updated on the Web. Although the number of feeds available today is impossible to catalog, FeedBurner, a Chicago-based outfit that manages feed publication information, currently tracks feeds for more than 150,000 publishers, from the average blogger to Reuters. That figure is up from about 30,000 at the beginning of the year. In January 2005, about 235,000 people subscribed to these feeds; by November, the number of subscribers had swelled to nearly 8 million.

Increasingly, these subscribers aren’t even aware that RSS is bringing them updated headlines through services like My Yahoo or My MSN – because the technology works so well behind the scenes that these providers haven’t bothered to single it out with a name. Similarly, “podcasting has been a huge trend in 2005, but a lot of people don’t realize that RSS is driving it,” says Eric Lunt, chief technology officer at FeedBurner. In fact, an October survey by Ipsos Insight, a marketing consultant, found that 27 percent of the U.S. population use RSS but are unaware of it, compared with just 4 percent who know what the term means. Whether or not users know the technical name for subscribable online media, though, 2005 was when “people recognized the value of the information coming to them on their own terms,” says Lunt.