Internet giants from Google and Facebook to Yahoo and Zynga are scrambling to adapt to an online world where people reach for smartphones or tablets instead of traditional computers.
Social games pioneer Zynga, which rose to stardom making titles played at Facebook's website, is cutting nearly a fifth of its staff as part of a move to focus on titles for mobile gadgets.
After taking over as chief executive at Yahoo last year, former Google executive Marissa Mayer laid out a turn-around strategy that made a priority of tailoring offerings to smartphones and tablets.
The dismal performance of Facebook's freshly-launched stock last year was blamed in large part on fears that it lacked tools to cash in on members who are increasingly accessing the social network from mobile devices.
Google has proved prescient by creating and giving away an Android mobile operating system that showcases its software and services on smartphones and tablets.
Even the Mountain View, California-based technology titan's seemingly offbeat "big bets" on Internet-linked Glass eyewear and Web-connected self-driving cars are seen by some analysts as shrewd moves to remain anchored in lifestyles.
"The head-mounted display makes the mobile user much more valuable because you can serve ads as they are walking and make them location-based," independent Silicon Valley analyst Rob Enderle said of Glass.
"With self-driving cars, the dashboard is a huge tablet; if the car is driving and someone is bored, you can serve up whatever you want."
Companies that staked claims with websites visited by people using desktop or laptop computers risk obsolescence if they don't adapt to Internet users switching to apps on smartphones or tablets.
Industry data shows that people are moving "aggressively" to apps and away from traditional websites, according to Gartner analyst Van Baker.
"It is important to cater to that mobile user," Baker told AFP. "That is the driving force in the market right now; the one device a person carries everywhere -- the smartphone."
Not only are the devices preferred by Internet users changing, so is their behavior.
Gartner research shows that people using smartphones access the Internet an average of 20 times a day with sessions lasting about a minute, compared with four times daily for about 35 minutes a pop on traditional computers.
"It is a big challenge, because the behavior associated with a smartphone is dramatically different from a notebook computer," Baker said.
"Your experience needs to be two clicks deep and be done in a minute," he continued. "If it takes any longer, they are gone."
Smartphones in particular have small screens, raising the risk of people being annoyed by advertising.
Mobile devices also allow location, calendar information and other contextual data to be woven into services to win people over with desirable information at just the right moments and places.
"The opportunity to be relevant or helpful is much greater because of the contextual information," said Forrester analyst Charles Golvin.
"If you interrupt me and adopt the old get-in-your-face approach of many marketers, you are much more likely to sour any potential relationship."
Internet companies don't have the luxury of focusing on either mobile devices or traditional computers; they must tailor offerings for both, according to analysts.
"Mobile first is correct, but it is not mobile only," Golvin said.
"You need to enable your customers to reach you where and when they choose to and on the device that happens to be in their hand at that moment."
Established Internet companies tend to be well-positioned to adapt to engaging people on mobile devices.
"The fundamentals of delivering your experience digitally are still there at the core whether it is going to a PC or a browser or to a mobile device," Golvin said, referring to established operations such as Facebook and Yahoo.
"It is less of a disruption than it is a transition."
However, the ability to bypass running websites makes it easier for startups to blaze into the market with mobile apps.
Zynga faces the added challenge of being in a hits-drive business in a world where loyalty to apps is fleeting.
Most of the people who download a mobile app at launch abandon it within three months, according to Gartner.
"The life of 'Draw Something' or 'Farmville' can be even more compressed in the mobile world," Golvin said, referring to Zynga titles.
"A game is a hit, people engage and then the next hit comes along and takes up their time."