It's not clear how these under-13 products will work, but they may change the way they look or the kinds of data they present. In the most specific example, Diwanji recounted a story about her daughter typing "trains" into Google Search hoping for results about Thomas the Tank Engine, but getting an Amtrak schedule instead.
In the US, one of the biggest considerations when designing online products and services for kids is the Children's Online Privacy Protection Act, or COPPA. It dictates how information can be collected from and presented to kids under the age of 13—changes to the law effective in July of 2013 include multiple stipulations related to privacy policies, parental oversight, and security requirements for data collected from young children. Since the vast majority of Google's revenue comes from advertising and the value of the company's ads is tied to its trove of user data, COPPA compliance will obviously be important to users and Google alike (Yelp was fined $450,000 earlier this year for COPPA violations).
Google isn't the first company to try and make its products more kid-friendly. Apple introduced a new kind of Apple ID alongside iOS 8 and OS X Yosemite's Family Sharing feature in the fall, a type of account that allows kids to buy and download apps but only with explicit oversight by and permission from a parent. Child-specific accounts and products like these could actually be helpful for parents who want to protect their kids' privacy.
"We want to be thoughtful about what we do, giving parents the right tools to oversee their kids' use of our products," said Diwanji.
Editor: It is interesting to note that a number of years ago research was done showing that the primary decision makers of the household is 10 years old. So marketing to children has a much greater impact than previously throught - including such purchases as cars and houses!