What is native advertising? Is it a new practice, or little more than a new name? Is it legal?

Is it the same as content marketing? How does it relate to what was sold to us as the greatest content marketing strategy ever, i.e. social media marketing?

Does native advertising happen only on social media, or has the practice spread to newspapers?

Does native advertising work? For whom does it work? Does it have negative consequences for society?

How was the problem dealt with in the past? Should native advertisement be deregulated, or should it be more seriously regulated? Which other problems may native advertising face?