The trans Atlantic slave trade was a very dark period in our recent history from the late 17th century to the early 19th century. It was a cruel enterprise and even though there were many attempts from righteous people during this time to stop the practice, they were mostly unsuccessful.
The remaining people in Africa who were not themselves slaved, ended up one way or another participating in the lucrative slave business. The trade affected various groups of people in different ways. Some of the groups or societies benefited economically while other groups in the interior of Africa suffered negative consequences, because they were selected to be taken as slaves. Specially those living in the coastal areas.
The societies were categorized in this manner:
1) Societies which were mainly the object of slave raids or slave producing societies.
2) Societies which were mainly engaged in the practice of capturing slaves to supply the markets.
3) Societies that mainly engaged in the sales of slaves. They acted as middle man or retailers, selling the slaves to European buyers.