Today, similarity of cultures around the world has increased for many reasons. One important reason is immigiration and the other one is social media. I believe that it is a negative trend because of probability of forgetting culture by new generation people.
These days people from around the world immigrate to abroad for many reasons such as working in other countries or changing their living place. Indeed, by immigiration, culture of these people also moves to other habitats. For example, people in destination country often share their traditions and culture with locals, either at school or in social relation with others. This could happen in reverse, so they learn about target country culture and mix it with their one. Moreover, the other important factor is social media. People in the world use social media infrastructure to make connection with other cultures in many ways such as making friends, participation in volunteer virtual jobs or even becoming member of multi-culture groups. Social media provides virtual environment that people could transfer their believes and culture through it by chatting or sharing contents. In fact, by using social media cultures among the whole world mix with each other by people.
I strongly believe that similarity of cultures is a negative trend for many reasons. Unfortunately, young people are the most people who welcome to culture mixing, because they feel more convenient. Indeed, two reasons lead to forgetting culture by this group. First the lack on contact with their parents and grandparent as the main source of cultures and traditions background. The other one is using too much social media and lack of enough contact with family.
In conclusion, immigiration and social media are the most important factor of similarity of the cultures among countries. I believe that it is a negative trend because it may caused to forget local cultures and traditions among the young people.