Globalization of culture describes an increase in uniformity of cultural practices throughout the world. Culture is made up of many different aspects including language, food, architecture, mannerisms, symbols, clothing, and ideals.
Our planet has become increasingly connected on a massive scale over the past millennium. Let's think back to the year 1,000 CE- when Europeans were just beginning to visit the New World. At this time, most people around the world lived a relatively isolated lifestyle. The state of technology demanded that much of a person's life be devoted to subsistence and not much else. It was not uncommon for someone to die in the very same house they were born in. People who did travel primarily did so for business reasons, and this was the nature of most cultural interchange at the time. Due to the low literacy rates of the time, letter-writing was uncommon, and the nature of infrastructure did not foster interchange which might have caused material culture to be more uniform. Whereas today, you could easily buy the same style of t-shirt or cup in almost any part of the world, a thousand years ago the styles of goods were highly dependent on resources available and the traditions of local artisans. Most goods were produced in the home, for the home, so the trade of a surplus of goods did not often have far-reaching destinations. However, the import and export of certain luxury goods like spices drove the economy throughout the Middle Ages.
Advances in transportation and communications technology has rapidly "connected" the world. The invention of steam-engines, while a little unimpressive to a modern person, had a profound impact on transportation and trade during the nineteenth century. Improvements in infrastructure (like roads) and literacy enabled written exchange from place to place, even from one side of the globe to the other!
Since the late twentieth century, the degree of globalization has skyrocketed. Widespread use of the internet and cellular phones enables connections between people from all over the globe. Much of the increase in uniformity is unintentional. Not only are goods being transported around the world, so is culture. For example, the trade of coffee beans (beginning in the 15th century) has a major impact on the life we live today. Do you know anyone who likes to have a cup of coffee every morning? Coffee, native to Ethiopa, has become a common part of culture all over the world. Not only is the good transported, many people have a preferred "ritual" for when, where, and how to drink coffee, influenced by centuries of cultural exchange surrounding the coffee bean.
Globalization has both positive and negative aspects. It is a boon to humankind to be able to share information so quickly across such great distances. However, much of the trade and industry which promotes globalization thrives off of the exploitation of human labor.