Apple stores around the world have become impromptu shrines to the company's co-founder Steve Jobs.
People left flowers and candles at the stores as millions mourned the death of Steve Jobs, a technology pioneer who played a key role in changing the global electronics industry.
Reaction from London
Business competitors, colleagues, political leaders and fans are paying tribute to Jobs, who co-founded Apple in 1976 and used it to introduce successful products including the Macintosh computer, iPod, iPhone and iPad.
Reaction across the world
Apple co-founder Steve Wozniak told CNN that Jobs was a "great visionary and leader," and a "marketing genius." Wozniak said Jobs believed in technology as the future.
U.S. President Barack Obama called him one of America's "greatest innovators." Facebook founder Mark Zuckerberg thanked Jobs for showing that what he built can "change the world."
Former U.S. President Bill Clinton said Jobs' passion for his work and his courage in fighting his cancer were an inspiration.
The news of Jobs' death reached far around the world and up to the International Space Station, where commander Mike Fossum called him a rare person who had the "energy, skill and genius" to make things happen. Fossum said the world will miss Jobs a lot
Jobs died Wednesday at age 56 after a long battle with pancreatic cancer. People have since been flocking to Apple stores, where they have laid flowers, pictures, candles and notes acknowledging what Jobs meant to them and how he changed the world.
There has also been an emotional outpouring on Internet blogs. Twitter is experiencing record posts in an online tribute that at its peak saw nearly 10,000 comments a second.
The death of Jobs also is being felt strongly in Asia, where the products he pioneered are largely made and immensely popular.
Millions of tributes to Jobs appeared Thursday on microblog sites in China, where members of the world's largest on-line community routinely line up for days to purchase each new Apple product.
Microsoft, Google, Sony and Samsung, all technology competitors of Apple, have paid tribute to Jobs.
Praise from tech competitors
Microsoft Chairman Bill Gates, Jobs' long-time rival and former business partner, said Wednesday Jobs' impact on the world of technology will be felt "for many generations to come." Gates, an early supporter of Macintosh computers, said working with Jobs was "an insanely great honor."
Samsung praised Jobs' "innovative spirit," calling him a "great entrepreneur." The two technology giants have been locked in a series of patent lawsuits since April, when Apple took legal action against Samsung for allegedly copying technology used in the iPhones and iPads to create its own line of smartphones and tablet computers.
President Obama said "there may be no greater tribute" to Jobs' success "than the fact that much of the world learned about his passing on a device he invented."
Recently appointed Apple CEO Tim Cook, who took over when Jobs stepped down in August, said Jobs' spirit will "forever be the foundation of Apple."
A memorial message on Apple's website says that fans can share their memories of Jobs by sending an email to the organization at firstname.lastname@example.org.
Some information for this report was provided by Reuters.