Narasu Rebbapragada

Depending on the neighborhood, the fire-engine red “People Love Us on Yelp” sticker outnumbers sedate-looking “Zagat Rated” emblems or fading newspaper reviews on restaurant doors. There’s no mistaking the power--and, let’s face it, the sheer entertainment value--of candid reviews written by regular diners rather than food-industry elite.

And recently, a report written by Harvard Business School assistant professor Michael Luca showed just how powerful a Yelp rating can be: Luca found that a one-star increase in the rating of an independent restaurant leads to a 5 to 9 percent increase in revenue.

UPDATE [March 8, 2012]: The Department of Justice said yesterday it plans to sue Apple and five of the largest e-book publishers in the US on charges that they acted together to push up the price of electronic books, the Wall Street Journal reports.

As discussed in this PCWorld investigative feature from last May, e-book publishers deeply resented large retailers like Amazon selling their e-books at deeply discounted rates under a "wholesale model." Apple introduced a new model--called the "agency" model--where the publisher sets the price of the e-book and the retailer sells it for that price, taking a 30 percent fee.

Like a lot of people, Kenny Thompson had trouble balancing a 40-plus-hour job with a fitness regimen. The 34-year-old food-market manager, a resident of Morristown, New Jersey, used to work out regularly when he was younger, but over the past couple of years he had become more inactive. Recently that all changed, thanks to his Xbox 360 Kinect add-on and a game called Your Shape: Fitness Evolved.

An avid gamer who realized the need for a lifestyle change, Thompson entered Ubisoft's Your Shape: Fitness Evolved Bootcamp contest for a chance to be among the first to play the game. Since then the game has become part of a regular commitment to diet and exercise, and Thompson has lost more than 15 pounds. His favorite feature in Your Shape: Fitness Evolved is cardio kickboxing, but he can also try one of the many programs designed by experts from Men's Health and Women's Health magazines. Through Kinect's motion sensors, which track more than 50,000 points on his body, the game gives him feedback on how he's moving through the exercises.

On many mornings, Ji Kim loads his backpack with three Apple devices--an iPhone, an iPad, and a MacBook Pro--before he taking the bus to his downtown San Francisco office. When giving presentations from his laptop, he uses his iPhone to access data from the Internet so as not to mess with the PowerPoint slides. Sometimes towards the end of the day, he'll carry those same devices to the quiet solitude of a café near his house so he can finish off some work uninterrupted.

When he returns to the San Francisco apartment that he shares with his girlfriend, those devices join an Amazon Kindle e-book reader, a Sony PlayStation 3 game console, an Apple Mac Mini (turned into an entertainment center), and a PC that also live there.

Imagine if you could learn to fly a helicopter by downloading software directly to your brain. Imagine if your eyes could see an object, overlaid with data, miles away in the dark. These science-fiction scenes from The Matrix and Terminator movies may be less fictional in the future, thanks to the fascinating science behind medical implants.

The gargantuan amount of high-quality user data on Facebook is causing everyone--from marketers to hackers--to salivate like dogs gazing at a steak. They all want a piece of you.

Thanks to Facebook's Open Graph API (which simplifies the development of third-party applications that interoperate with the social networking site) and social plug-ins (which essentially splash Facebook's "Like" button all over the Internet), people who are interested in your data are getting a chance at a much choicer cut of it. (For more, read "How Facebook Plans to Dominate the Web.")

With personal trainers producing YouTube fitness videos, iPod Nanos sporting pedometers, and yogis practicing tree pose using the Wii Fit--technology has become one of the best ways to set and maintain fitness goals. We consulted sports professionals, fitness enthusiasts, and tech companies to find the latest and most interesting hardware, software, and Websites that you can use to get in shape and stay the course.

General Fitness Gadgetry

A portable music player is still as important to workouts today as it was when the first wave of yellow Sony Walkmans hit gyms in the early 1980s. (For more tech oldies, see "The 50 Greatest Gadgets of the Past 50 Years.") One new fitness-focused model is the Philips Activa ($130), which adds workout software to a combination portable media player and FM radio. Enter your age, weight, and height, and the Activa will count calories, time, or distance as you engage in an activity such as running, cycling, or rowing. Use the TempoMusic feature in conjunction with the up and down arrows to find songs that match your speed, so you won't find yourself listening to speed metal during your cooldown. Need a little encouragement? Program a male or female voice to update you (whenever you hit the Boost button) on calories burned, distance covered, or simply the virtues of staying the course. Plus, you can download all of this information to your PC and track it over time.