When you visit a website, you often find yourself waiting and waiting for advertisements to load. Video starts playing automatically, and animated ads jump in front of what you were there to see. The seconds tick by.
It doesn't have to be this way.
There are easy ways to block such annoyances, and Apple is now permitting apps that block ads in its Web browser for iPhones and iPads.
All this might help users navigate, but it also threatens the livelihood of websites and publishers that depend heavily on advertising revenue — companies like Google, Hulu and The New York Times. While the rise in ad blocking isn't causing panic yet, publishers and content creators are watching.
Already, some websites are taking steps to reduce the annoyance so users won't turn to ad blockers. They are also subverting the ones out there to make sure they get paid for delivering news and entertainment.
"It is possible to be too alarmist about ad blockers, but it's a very real phenomenon," said Joshua Benton, director of the Nieman Journalism Lab at Harvard University.
It's one thing if just 5 percent of iPhone users install an ad blocker; it's another if 80 percent do, Benton said. If today's ad practices get too annoying, he said, they could disappear just like pop-up windows, which many browsers now block automatically in response to consumers' annoyance with them.
Over the years, websites have been more aggressive at delivering ads that break through the noise and target specific customers more precisely. But websites are also filling unsold ad space by turning to ad brokers to deliver pitches that are less and less relevant.
Every little bit can slow down or freeze your browser.
"I think publishers got very out of hand in terms of what they put on," said Dean Murphy, 28, a Yarm, England, app developer who responded by creating Crystal, a $1 ad blocker for Apple devices.
Craig Smith, a 47-year-old website developer in Musselburgh, Scotland, said Twitter started showing him ads for adjustable waistband trousers not long after he and his followers discussed about how ridiculous his grandfather's trousers looked in a photo.
"All of a sudden you're getting hammered with stuff you've got no interest in," he said. "It just makes the whole browsing experience really unpleasant."
PageFair, a firm that seeks to counter ad blockers, says worldwide usage of ad blockers grew 41 percent from last year to nearly 200 million people. That's 6 percent of Internet users worldwide, including 16 percent in the U.S., 37 percent in Greece and 25 percent in Germany. PageFair estimates these tools will block nearly $22 billion in ad revenue this year and $41 billion next year.
The threats to websites are about to get bigger. The ability to block ads, long available on traditional computers, arrived on Apple's mobile devices with a recent software update, iOS 9. Apps with these capabilities — going by such names as Purify Blocker and Blockr — quickly became top sellers. These tools affect only the Safari browser and won't block ads inside apps such as Twitter, Facebook and Apple's own News app.
Google's Android system also allows ad blockers in Web browsers such as Firefox, as long as they don't affect unrelated apps.
Many websites already have countermeasures for ad blockers.
Hulu, for instance, simply replaces commercials with an unskippable message prompting you to turn your ad blocker off. Or, you can pay Hulu $12 a month to go ad-free.
Meanwhile, some companies are paying developers of ad blockers such as Adblock Plus for the right to bypass them. Companies that benefit a lot from search ads, like Google and Microsoft, pay for the privilege, the Financial Times reported. Microsoft declined to confirm the report. Google didn't respond to requests for comment, although the list of Web addresses that get a pass includes many from Google. Hulu declined comment.
All this raises questions about the role of ad-blocking companies. Ad blockers streamline the user experience without contributing back to the digital economy, even as they seek to make money by charging websites for the right to nullify their impact. Smaller websites can get a free pass from ad blockers, but only if they forego revenue from video ads or other display ads deemed intrusive.
Perhaps there's another way — a truce, of sorts.
Some companies are trying to create a smoother experience to get at the root cause of consumer frustration.
Apple's News app, Facebook's Instant Articles and SnapChat's Discover all seek to speed up online journalism and cut back advertising, while sharing revenue with news outlets.
The New York Times has ads in Apple News, but it's looking for ways to make them less obtrusive. For instance, the Times says it's selling ads by time of day and encouraging marketers to tailor their messages accordingly, like making ads that help readers prepare for the day in the morning, but entertain them at night.
The Washington Post has been testing whether visitors with ad blockers installed would respond to being redirected to a page that asks them to pay for a subscription. And on Tuesday, the Post said all of its articles will be available through Facebook's new service for "lightning-fast" reading, sharing and commenting from Apple devices.
"The market wouldn't be robust for ad blockers if some ads weren't intrusive, creepy, hold you hostage or slow down your experience," said Jed Hartman, the Post's chief revenue officer. "Everything should be on the table: fewer ads, different types of ads, no ads."
Meanwhile, the industry group Interactive Advertising Bureau is pushing for "viewable" ads that load only when that part of the page is visible. That way, marketers don't pay for ads that aren't seen, and sites should load faster.
Randall Rothenberg, the group's CEO, called ad-blocking practices "definitely immoral and unethical," yet he acknowledged that consumers turn to blockers because they are fed up.
"Consumers are speaking and you've got to listen to them," he said.