In a Consumer Reports survey, 71 percent of respondents said they were very concerned about online companies selling or sharing information about them without their permission.
More than half of respondents also said they were very concerned about advertisers targeting kids with personalized ads based on data collected while kids surf the Web; companies holding on to their data, even when they don't need it anymore; and data about their online activities and purchases being used to deny employment or affect their ability to get a loan.
For tips on how you can best protect your privacy while online, see our guide to online security, which includes protecting kids while on Facebook.
Our survey also found that, 65 percent of smart phone owners said they were very concerned that apps could access their contacts, photos, location and other data on their devices without their permission.
Consumers Union, the public policy and advocacy arm of Consumer Reports, submitted the survey results to the National Telecommunications and Information Administration as public comment on a proposal to develop voluntary codes of conduct for consumer data privacy.
Ioana Rusu, regulatory counsel for Consumers Union, said "Your personal data ought to be treated with respect, and you ought to have more of a say in how it's used."
New FTC privacy proposal unveiled today calls for added consumer protection online