Pivoting from talking about the companies' track record on online privacy, Paul said he worries about the government using the Patriot Act to obtain a sweeping amount of people's information from companies — all with immunity from future lawsuits.
In these situations, Paul said companies like Google and Facebook should "stand up and defend privacy."
Still, he stressed that Web companies have an obligation to uphold their privacy promises to users.
"Ultimately, the people going after privacy are the government, and if people mistake Google for government, then we’re in for a big problem. If people begin to mistake Gmail for Government-Mail, they’re liable to get swept up in the same net of people supporting privacy," Paul said in the interview.
"I see a distinction, and I think it’s in their interest as a company to fight hard for privacy, fight hard to protect the contractual arrangement their customers have with them."
Google and Facebook have come under fire from lawmakers and regulators for not doing enough to protect people's personal information online. Both companies have settled charges with the Federal Trade Commission over violating their privacy policies.
Paul has been active on Fourth Amendment and online privacy issues in the Senate.
The rumored 2016 presidential contender recently introduced a bill that would require the government to obtain a warrant to access any electronic records held by a third-party. Paul has also backed efforts to pass email privacy legislation that would require police to obtain a warrant before seizing emails, Facebook messages or other types of electronic communications.
Under current law, authorities only need an administrative subpoena that's issued without a judge's approval to read emails that are more than 180 days old.
He also backed a manifesto with his father, Rep. Ron Paul (R-Texas), that opposed efforts by governments to regulate the Internet and disrupt Internet freedom.
In the interview with Wired, Paul said his libertarian views on email privacy rights and other issues could resonate with voters in California, a traditionally Democratic-leaning state that President Obama easily won in the 2008 and 2012 elections.
During his fundraising swing in Silicon Valley, Paul has visited Google, Facebook and eBay. The trip has been viewed as an attempt to woo support from top Silicon Valley executives and the wider tech crowd.
He is hosting two question and answer sessions on microblogging website Twitter on Friday, which has the hashtag #randchat. The first will be focused on discussing the Kentucky senators views on tech policy and civil liberties issues.
Paul admitted to Ackerman that he is weighing a presidential bid in 2016, but said he plans to hold off on making a final decision "for about a year."