Nearly half of all U.S. Internet users say privacy and security concerns have stopped them from doing basic things online, such as posting to social networks, expressing opinions in forums or even buying things from websites.

A report by the National Telecommunications and Information Administration (NTIA) found that Americans are increasingly concerned about online security and privacy at a time when data breaches, cybersecurity incidents, and controversies over the privacy of online services have become more prominent. These concerns are prompting some Americans to limit their online activity, according to data collected for NTIA in July 2015 by the U.S. Census Bureau. This survey included several privacy and security questions, which were asked of more than 41,000 households that reported having at least one Internet user.

NTIA said that the most direct threat to maintaining consumer trust is negative personal experience. Nineteen percent of Internet-using households—representing nearly 19 million households—reported that they had been affected by an online security breach, identity theft, or similar malicious activity during the 12 months prior to the July 2015 survey. Security breaches appear to be more common among the most intensive Internet-using households. For example, while 9 percent of online households that used just one type of computing device (either a desktop, laptop, tablet, Internet-connected mobile phone, wearable device, or TV-connected device) reported security breaches, 31 percent of those using at least five different types of devices suffered this experience.

Similarly, 22 percent of Internet-using households that used a mobile data plan to go online outside the home experienced an online security breach, compared with 11 percent of those not using data plans while outside the home. Perhaps not surprisingly, these figures suggest the prevalence of data breaches is higher among segments of our population that are constantly connected.

NTIA also asked households to identify what concerned them the most about online privacy and security risks. Interviewers did not suggest possible answers when asking this question, and respondents were free to give multiple answers or to say that they had no concerns. Despite the lack of prompting, 84 percent of online households named at least one concern they had about online privacy and security risks, and 40 percent cited at least two different concerns. By far the most frequent concern—shared by 63 percent of online households—was identity theft. Other common concerns included credit card or banking fraud, data collection or tracking by online services, loss of control over personal data, data collection or tracking by government, and threats to personal safety.

Privacy and security concerns were even more prevalent among online households that had been affected by a security breach during the year prior to the survey. Seventy percent of such households named identity theft as one of the issues that concerned them the most, compared with 62 percent of their peers that had not experienced a breach. We observed the same pattern across the board; for example, 30 percent of breach-affected online households were concerned about data collection or tracking by online services, versus 21 percent of their unaffected counterparts.

NTIA said "It is clear that many Americans have serious concerns about privacy and security on the Internet. NTIA’s most troubling finding comes from a series of questions about whether households had refrained from participating in certain online activities due to privacy or security concerns during the year prior to the survey. Forty-five percent of online households reported that these concerns stopped them from conducting financial transactions, buying goods or services, posting on social networks, or expressing opinions on controversial or political issues via the Internet, and 30 percent refrained from at least two of these activities. Privacy and security concerns deterred each of these important activities in millions of households, and this chill on discourse and economic activity was even more common among online households that either had experienced an online security breach or expressed two or more major concerns about privacy and security risk." 

Online households were even more likely to refrain from a particular activity when they had privacy or security concerns related to the activity in question. Among households citing identity theft as a concern, for example, 35 percent reported that they had refrained from conducting financial transactions online during the year prior to the survey, compared with 18 percent of other online households. Similarly, 33 percent of online households concerned about credit card or banking fraud declined to buy goods or services using the Internet, compared with 21 percent of their peers who had not expressed that particular concern. The apparent fallout from a lack of trust in the privacy and security of the Internet also extends beyond commerce. For example, 29 percent of households concerned about government data collection said they did not express controversial or political opinions online due to privacy or security concerns, compared with 16 percent of other online households.

https://www.ntia.doc.gov/blog/2016/lack-trust-internet-privacy-and-security-may-deter-economic-and-other-online-activities