Entrusting companies with your personal information enlists the same gravity as telling your best friend a secret. You want to know the one who holds this private information doesn't share the details behind your back. But for customers interacting with companies online and via mobile devices, trust can be a difficult bond to build.

According to TRUSTe's 2012 U.S. Online and Mobile Privacy Perceptions Report, conducted by Harris Interactive, online privacy remains the primary concern for U.S. adults age 18 and older. While 94 percent of respondents agree that privacy is important, 55 percent consider online privacy to be a very important issue that they think of frequently. The study, which polled 1,033 U.S. adults and 554 U.S. smartphone users, explores how today's customers respond to online and mobile advertising with respect to the information extracted from such interactions:

• Compared to one year ago, 60 percent of adults surveyed are more concerned about online privacy today.
• Sixty-nine percent of respondents trust themselves most when it comes to safeguarding their own personal information online, up from 45 percent in 2011. Of those polled, 76 percent will not allow companies to share their personal information with third-party companies, while 90 percent use browser controls to protect their privacy.
• When it comes to online behavioral advertising (OBA), 58 percent of those polled definitively indicate that they "do not like" such tactics, with 40 percent saying a targeted ad made them feel uncomfortable. However, 61 percent are more inclined to do business with a site that gives them the opportunity to opt out of OBA.
• Fifty-three percent of respondents believe their personally identifiable information is attached to their browsing histories.
• Of those smartphone users polled, 42 percent also cite privacy and security as top concerns.
• Sixty-two percent of smartphone users are aware that advertisers track their mobile activities in order to offer relevant advertisements. However, only 1 percent of users like this practice.
• Less than 10 percent of smartphone users are willing to share their location information, browsing behavior, home address, or contacts with mobile applications, while 85 percent refuse to download apps they don't trust.

Key takeaway: While customers continue to place privacy issues at the top of their list of concerns, companies must be sure that managing such customer worries remains at their top of their list. For instance, customers are beginning to rely on certifications and seals to indicate how trustworthy a company may be, with 49 percent of those polled checking for such markings. Customer awareness of the DAA's AdChoices Icon has increased three-fold since its introduction in 2011, and recognition of TRUSTe's seal has jumped from 64 percent recognition in 2011 to 72 percent in 2012. Using such certifications boosts customer confidence in a company's site, thus establishing a foundation for trust.