But some purchases still happen mostly offline, including one of the most personal: prescription eyeglasses.
Some Web pages are designed so that you cannot store their information offline, including those that use Active Server Pages, or A.S.P., to generate content.
A similar attack on the US-based Dyn web domain provider in October knocked a host of prominent websites offline, including Spotify, Twitter and Reddit.
In retaliation, hackers affiliated with Anonymous briefly knocked dozens of Web sites offline, including those of the F.B.I., the White House and the Justice Department.
Google also said that many apps would operate offline, including Gmail, Google Docs and Google Calendar and, when workers need a break from all that productivity, the game Angry Birds.
On the day the exchanges were due to open, much of the federal government would go offline, including a big portion of the Health and Human Services Department that is running the coverage expansion.
To counter what's been called psychological virtual warfare, Anonymous, the hacking collective, has taken certain Web sites offline, including the Bank of Jerusalem and the Israel Ministry of Foreign Affairs, and is compiling means for Gaza residents to get online if Israel downs their servers (a "Gaza care package").
The shutdown came in the midst of a tussle over antipiracy legislation in Washington, and it inspired the hacker group known as Anonymous to knock a number of high-profile Web sites offline, including those of the Justice Department and the Motion Picture Association of America.
Eight members of Congress have opened an investigation into data brokers – the companies that collect, analyze and sell consumer data both on and offline – including big players in the industry like Acxiom and Epsilon and some of the large consumer report companies.
On that morning, 30% of U.S. refinery capacity was offline, including 5% that had remained shut in since Katrina.
At Disrupt, Hughes and Heiferman will discuss how social media can foment positive fallout offline, including in places that aren't wired and wealthy.
