The online economy—from search to email to social media—is built in large part on the fact that consumers are willing to give away their data in exchange for products that are free and easy to use. The assumption behind this trade-off is that without giving up all that data, those products either couldn't be so good or would have to come at a cost.

    But a new working paper, released this week by Lesley Chiou of Occidental College and Catherine Tucker of MIT, suggests that the trade-off may not always be necessary. By studying the effects of privacy regulations in the EU, they attempted to measure whether the anonymization(匿名化) of search data hurts the quality of search results.

    Most search engines capture user data, including IP addresses and other data that can identify a user across multiple visits. This data allows them search companies to improve their algorithms(算法) and to personalize results for the user. At least, that's the idea. To determine whether storage of users' personal data improves search results, Chiou and Tucker looked at how search results from Bring and Yahoo differed before and after changes in the European Commission's rules on data retention(数据保存). In 2008 the Commission recommended that search engines reduce the period over which search engines kept user records. In response, Yahoo decided to strengthen its privacy policy by anonymizing user data after 90 days. In 2010 Microsoft changed its policy, and began deleting IP addresses associated with searches on Bring after six months and all data points intended to identify a user across visits after 18 months. In 2011 Yahoo changed its policy again, this time deciding to store personal data longer—for 18 months rather than 90 days—allowing the researchers yet another chance to measure how changes in data storage affected search results.

    The researchers then looked at data from UK residents' web history before and after the changes. To measure search quality, they looked at the number of repeated searches, a signal of dissatisfaction with search results. In all three cases, they found no statistically significant effect on search result quality following changes in data retention policy. In other words, the decision to anonymize the data didn't appear to impair the search experience. “Our results suggest that the costs of privacy may be lower than currently perceived,” the authors write, though they note that previous studies have come to different conclusions.

When milk arrived on the doorstep

    When I was a boy growing up in New Jersey in the 1960s, we had a milkman delivering milk to our doorstep. His name was Mr. Basille. He wore a white cap and drove a white truck. As a 5-year-old boy, I couldn't take my eyes off the coin changer fixed to his belt. He noticed this one day during a delivery and gave me a quarter out of his coin changer.

    Of course, he delivered more than milk. There was cheese, eggs and so on. If we needed to change our order, my mother would pen a note-“Please add a bottle of buttermilk next delivery”-and place it in the box along with the empty bottles. And then, the buttermilk would magically appear.

    All of this was about more than convenience. There existed a close relationship between families and their milkmen. Mr. Basille even had a key to our house, for those times when it was so cold outside that we put the box indoors, so that the milk wouldn't freeze. And I remember Mr. Basille from time to time taking a break at our kitchen table, having a cup of tea and telling stories about his delivery.

    There is sadly no home milk delivery today. Big companies allowed the production of cheaper milk, thus making it difficult for milkmen to compete. Besides, milk is for sale everywhere, and it may just not have been practical to have a delivery service.

    Recently, an old milk box in the countryside I saw brought back my childhood memories. I took it home and planted it on the back porch （门廊）. Every so often my son's friends will ask what it is. So I start telling stories of my boyhood, and of the milkman who brought us friendship along with his milk.

    Why do I volunteer with Big Brothers Big Sisters of America? I have many reasons. Perhaps the biggest reason is that someone volunteered to help me. Years ago, I was on the other side of the table. I was lonely and felt kind of lost. More than once, I found myself on the wrong side of a jail cell(牢房). If someone hadn't stepped in, I probably wouldn't even be here right now.

    I've seen the work that Big Brothers Big Sisters has been doing all over the country and I'm pleased to be part of it. I've never done anything that made me prouder than my volunteering work. Big Brothers Big Sisters helped me get my head on straight. There are no words to describe the joy I get from helping somebody turn their life around.

    Don't tell anyone I said that, but volunteering is probably the fastest way to get over sadness or depression. Every time I start to feel bad, I talk to someone who needs my help and it makes me feel better and worse all at the same time. I feel better, because doing good things fills me with a sense of pride. I feel worse because I feel I have no right to complain about my situation especially when I hear what others are going through.

    I've come a long way from where I was. Volunteering is how I want to leave my mark on the world. I recommend volunteering work to everybody, especially for somebody who isn't sure where they're going in life. Helping someone find their path is often the best way to find yours.

    Getting rid of dirt, in the opinion of most people, is a good thing. However, there is nothing fixed about attitudes to dirt.

    In the early 16th century, people thought that dirt on the skin was a way to block out disease, as medical opinion had it that washing off dirt with hot water could open up the skin and let illnesses in. A particular danger was thought to lie in public baths. By 1538, the French king had closed the bath houses in his kingdom. So did the king of England in 1546. Thus it began a long time when the rich and the poor in Europe lived with dirt in a friendly way. Henry IV, King of France, was famously dirty. Upon learning that a nobleman had taken bath, the king ordered that, to avoid the attack of disease, the nobleman should not go out.

    Though the belief in the merit of dirt was long-lived, dirt has no longer been regarded as a nice neighbor ever since the 18th century. Scientifically speaking, cleaning away dirt is good to health. Clean water supply and hand washing are practical means of preventing disease. Yet, it seems that standards of cleanliness have moved beyond science since World War Ⅱ. Advertisements repeatedly sell the idea: clothes need to be whiter than white, cloths ever softer, surfaces to shine. Has the hate for dirt, however, gone too far?

    Attitudes to dirt still differ hugely nowadays. Many first-time parents nervously try to warn their children of touching dirt, which might be responsible for the spread of disease. On the contrary, Mary Ruebush, an American immunologist(免疫学家), encourages children to play in the dirt to build up a strong immune system. And the latter position is gaining some ground.

                                                                                          Educational Programs for Kids

    Are you interested in helping your child continue his or her education beyond the typical school day? If so, then educational programs for kids may be what you're looking for.

    Where to Find Educational Programs?

    Many kids who are struggling in school may benefit from an after-school tutoring session or homework club. Check with your child's school, your local library or the park district for a list of available programs. You can also check with the local Boys and Girls Club, YMCA, church or youth center. Depending on your child's interests and strengths, consider art, community service, drama, music, creative writing, sports, cooking or environmental programs.

    What Educational Programs Are Provided by Organizations?

    The organizations mentioned above provide educational programs for kids, such as a community your child can be a part of and programs that focus on education, health, leadership, recreation and fitness.

   Another possibility is the Boy Scouts of America or the Girl Scouts. These are two separate organizations that can potentially provide your child with a sense of accomplishment, self-confidence and belonging. Both organizations will provide your child with many learning experiences and activities both indoors and outdoors.

    What Kind of Program Is Best for My Child?

    The type of educational program that's best for your child is subjective and based on many factors, including your child's age. If your child is in primary school, educational programs can help him or her develop as a person and gain leadership skills, a sense of self-worth and the ability to cooperate with others. By the time your child is in high school, his or her involvement with educational programs and other extracurricular activates can be key elements when your child is applying to college.

    When you help your child to pick an educational program, carefully consider what your child needs and what every option offers.

    Did anyone find the names of "Great Britain", "the United Kingdom", "England" and "the British commonwealth" which have the same meaning? Strictly speaking, these names all refer to something different. None of them are exactly the same as any of the others.

    The British isles refer to the main islands and several thousand small ones as well, which you can see on the map. Great Britain, or Britain, refers to the larger of the two main islands. But the word "Britain" is often used as a short form for the United Kingdom or you call it the UK.

    Now as for England, it refers simply to the largest of the three countries on the island of Great Britain. The United Kingdom is the name of the state and the official name of the country, which many people popularly refer to England.

    Finally, the Britain commonwealth is the usual name for what is left of the British Empire. This change shows the weakening of British Empire and the rising of the national liberation movements throughout the world today.