The world turned to social media to mourn the passing of
Mandela's death produced more than 3 million tweets in the first two hours after news outlets around the globe reported that the former South African president had died, according to measurement firm Topsy.
Video tributes posted on YouTube -- some of which had been uploaded months earlier, as Mandela's health failed -- drew fresh words of appreciation and grief.
A 21-minute video of Mandela's 1988 speech at Harvard University attracted renewed interest on YouTube, with one commenter, identified only as Science Life NY, recalling attending the world leader's presentation as a freshman.
"Thank you so much for showing both how strong and forgiving people can be."
A 13-minute video biography of Mandela has been viewed more than 400,000 views since it was originally posted in 2010 -- and brought multiple new comments, offering tribute to his life and regret at his passing. The same is true of a