What is the difference between the current H1N1 “swine flu” and H1N1 “spanish flu” of 1918?

Robert asked:


In 1918 H1N1 Strain of Influenza that got the nickname “Spanish Flu” because it was traced back to a pig farm in Spain, killed 50 million people, what is the difference between that Strain of Influenza and the current pandemic we are facing now?

H1N1 Symptoms