There are various kinds of definitions about what data mining is. The authors in  define data mining as “the process of extracting previously unknown information from (usually large quantities of) data, which can, in the right context, lead to knowledge”. Data mining is widely used in areas such as business analysis, bioinformatics analysis, medical analysis, etc. Data mining techniques bring us a lot of benefits. Business companies can use data mining tools to search potential customers and increase their profits; medical diagnosis can use data mining to predict potential disease. Although the term “data mining” itself is neutral and has no ethical implications, it is often related to the analysis of information associated with individuals. “The ethical dilemmas arise when data mining is executed over the data of an individual” . For example, using a user’s data to do data mining and classifying the user into some group may result in a variety of ethical issues. In this paper, we deal with two kinds of ethical issues caused by data mining techniques: informational privacy issues in web-data mining and database security issues in data mining. We also look at these ethical issues in a societal level and a global level.
Informational Privacy Issues in Web-data Mining
There is a debate between the benefits and potential informational privacy issues in web-data mining. There are large amount of valuable data on the web, and those data can be retrieved easily by using search engine. When web-data mining techniques are applied on these data, we can get a large number of benefits. Web-data mining techniques are appealing to business companies for several reasons . For example, if a company wants to expand its business and find more potential customers, it can use web-data mining techniques to analyze personal data and any other useful information. The company can also provide more personalized services to their existing customers by using web-data mining techniques . In general, those techniques can bring more profits to the company by having more customers and selling more products and services, or by reducing costs . So there is no doubt that web-data mining can be quite beneficial to businesses .
However, people’s informational privacy may be violated in the process of web-data mining. “Information privacy mainly concerns the control of information about oneself” . The authors in  point out that “informational privacy can be violated when information concerning an individual is obtained, used, or disseminated, especially if this occurs without their knowledge or consent”. Web-data mining is categorized into two three different types: content mining, structure mining, and structure mining . Content mining means analyzing the content available in web documents . The web documents can include text, images, audio files, etc. Structure mining aims to analyze the way in which different web documents are linked...