African Americans moved north to avoid slavery. They also moved north for more opportunity. <span />
You already got the answer!:D
The Atlantic slave trade was so harmful to African nations because Africa missed out on generations of economic, cultural, and political development.
Due to the sharp rise of globalization, along with technological innovations such as the Internet, cultural and economic exchanges between nations today have reached unprecedented levels--meaning that practically anything can be shared and have an impact on society.