Final answer:
The main concern with the wealth of big data available for marketers is the risk to data privacy and security.
Step-by-step explanation:
In the context of marketers and big data, the main concern is the issue of data privacy and security. With the wealth of data available, there is a risk of data breaches and unauthorized access to personal information. Recent incidents, such as the Target data breach and Healthcare.gov security compromise, have exposed millions of people to the threat of identity theft. This concern is also reflected in surveys where a significant percentage of people express worries about data use by companies and the government.
This is evidenced by the rising number of Internet users who express concern over the extent of personal information available online and instances of online harassment and theft. Protecting personal data and ensuring privacy are essential considerations in the age of big data.