World and business leaders have continued to pay tribute to Apple co-founder Steve Jobs who has died at the age of 56.
US President Barack Obama and Russian counterpart Dmitry Medvedev said Mr Jobs had changed the world, the BBC reports.
The Twitter microblog site struggled to cope with the traffic of tributes.
In his own tweet, Barack Obama wrote: "There may be no greater tribute to Steve's success than the fact that much of the world learned of his passing on a device he invented."
In China alone, more than fifty million messages have been posted on the Chinese equivalents of Twitter.
Millions of tribute messages have also been posted on social networking websites.
UK Prime Minister David Cameron said Steve Jobs had "transformed the way we work and play; a creative genius who will be sorely missed."
Tim Cook, who was made Apple's CEO after Mr Jobs stood down in August, says the firm had lost a visionary and creative genius.
He said his predecessor had left behind "a company that only he could have built, and his spirit will forever be the foundation of Apple".
Thousands of people all over the world have also been attending Apple stores to leave flowers, notes, and apples with a bite taken from them to mimic the company's logo.
The Apple co-founder has been credited with transforming digital technology and built a reputation as a forthright and demanding leader who could take niche technologies and make them popular with the general public.
He introduced the colourful iMac computer, the iPod, the iPhone and the iPad to the world. Shares in Apple dropped after the announcement on Wednesday of Mr Jobs' death, but quickly recovered.
