An application called Offtime limits customers’ access to apps they overuse and logs their activity to produce charts on how much time they spend on their phones. Another, called Moment, encourages people to share their phone use with friends to compete in a game of who can look at their phone the least. And a New York designer recently completed a crowdfunding campaign for the Light Phone, a credit-card-size phone that does nothing but make and receive phone calls and “is designed to be used as little as possible.”

Perhaps most radical is the NoPhone, a $12 piece of plastic that looks like a smartphone but actually does nothing. Van Gould, an art director at a New York advertising agency who moonlights as head of the nascent venture, said he and his partners had sold close to 3,200 NoPhones, which they market as a security blanket for people who want to curb their phone addiction but are afraid to leave home without something to hold on to.

Even though many are doubtless bought as gags, “Most people don’t think about phone addiction as a real thing until you’re like, ‘O.K., they’re buying a piece of plastic because they are worried about their friend,’ ” Mr. Gould said.

Adam Gazzaley, a neurologist and neuroscience professor at the University of California, San Francisco, said, “You have a population that is starting to say, ‘Wait, we love all this technology but there seems to be a cost — whether it’s my relationship or my work or my safety because I’m driving and texting.’ ”

In the days before apps, you searched online when you wanted something, and that was that. But now that the Internet is increasingly mobile and companies are more sophisticated about tracking users’ history and preferences, technology is less about “pulling,” through Google searches, and more about “pushing,” through smartphone notifications that are impossible to ignore because they cause our phones to light up and go ding.

Some products are trying to find a balance, like Google Now, a kind of digital assistant that uses data like location, Gmails and browsing activity to predict what a user might want next. Part of the idea is to bother you only when you need it. “If I’m about to forget my kid’s birthday I want the phone to scream at me until I do something about it,” said Sundar Pichai, Google’s senior vice president of products.

This also makes business sense. The more people trust Google to navigate their lives, the more they’ll use apps like Google Calendar and Gmail. And the more Google understands its users, the more it can fine-tune its advertising engine.