Each day, Inc.'s reporters scour the Web for the most important and interesting news to entrepreneurs. Here's what we found today:

Firefox will add a do-not-track button. Following up on our story from last week about digital privacy, Mozilla announced today that it will take the FTC's suggestion to add a 'do-not-track' feature to its web browser. Ostensibly, a do-not-track button would allow users to opt-out of marketing schemes that collect subtle information about a user's online search queries and preferences. However, challenges remain. "For Firefox's tool to work, however, tracking companies would need to agree to not monitor users who enable the do-not-track feature," the Wall Street Journal reported this morning.  "So far, no companies have publicly agreed to participate in the system, but Mozilla urged them to join in."

Are e-customers cheap? New research suggests that the majority of Internet users do indeed spend money online, but many seem reluctant to spend very much. "For years, the willingness of Internet users to pay for information has been the subject of much anxiety, speculation and investment on the part of companies," noted Alex Mindlin for the The New York Times. A recent telephone survey conducted by the Pew Internet and American Life Project that found that though 65 percent of Internet users pay for online content, most are fairly frugal. For example, users who buy music online only spend an average of $10 a month. The survey also found that college students, perhaps unsurprisingly, spend the most money online.

Meet Dr. da Vinci, your robot doctor. Inside Detroit's Henry Ford Hospital, doctors are sitting down to perform the delicate process of prostate and kidney surgery.  They're trusting that a medical robot, known as the da Vinci robotic system can do a better job than they can.  The idea for the robot doctor started back in 1980, but didn't start to sweep the medical industry until Dr. Mani Menon revolutionized the concept in 2000.  TIME reports that da Vinci robotic system is now used in more than 1,000 hospitals and clinics in the United States and 400 institutions around the world. Innovation comes at a high price, though. TIME notes the robot costs about $1 million.

Check Your Credit...Card Mint.com has released a revelatory infographic detailing the secrets behind the digits on your plastic. Mint explains that the numbers hold specific significance, noting "those 16 digits are there for a reason and, knowing a few simple rules, you could actually learn a lot about a credit card just from its number." Merchants take note: the sum of of the digits on the face of the card must be divisible by 10. If not, it's a fake.

Fitness legend LaLanne passes away. Founder of the modern physical fitness movement Jack LaLanne passed away on Sunday at the age of 96. Though the benefits of exercise and healthy eating are now universally accepted, LaLanne had to fight an uphill battle when he first started. "You can't believe what I went through in starting my business," LaLanne told Inc. in 2009. "In 1936, when I opened my first gym in Oakland, I had doctors telling people, 'If you start working out with Jack LaLanne, the women will start looking like men, and the old guys will die of heart attacks.' They thought I was just a dumb, musclebound guy. Now every doctor wants you to exercise and eat more fruits and vegetables." Even into his 90s, LaLanne started each day with two hours of workouts, according to The New York Times. "I can't die," he liked to say. "It would ruin my image." Check out more Inc. coverage on LaLanne.

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