We live in a multi-tasking world - just like contemporary Operating
Systems evolved from a single-user, single-tasking DOS, humans have finally
became multi-tasking in the 20th century. 2000 years ago Alexander the
Great was the only person who could do two things at once. Today, any
kid can watch TV, SMS/IM with friends, play a computer game,
read/update Facebook/Tweeter, check news, eat a meal - all at the same
time.