Today, the 12th of February 2015,
 is 25 -TWENTY FIVE -years since Nelson Mandela was released from prison in South Africa.  I remember vaguely the event, and the news coverage showed millions of exuberant people all over the world.  They seemed to be saying "If Mandela can be released in the last holdout of state-sanctioned racism (Apartheid), then everything can change!"
Of course, today one immediately asks "has everything changed?..or.has anything changed?".  The answer is both "absolutely" and "not really".  This is because racism isn't ONE problem.  It's a million, or more exactly, 12.7 billion problems.
So there's not ONE answer, and the question has to be asked again tomorrow.  What I mean is a person can choose to hire a black woman one day, and then tell his golf partner that 'they' shouldn't be allowed on the course the next.  The first decision doesn't give them a 'lifetime non-racist' stamp, and they are equally guilty regardless of their earlier actions in the latter instance.
The real attraction of racism (and sexism and many other 'isms') is the ease it provides any diliemma, problem, action, issue, or decision.  It's so much easier to say 'everyone who works at the McDonald's in our neighborhood is black even though no one in our neighborhood is black, because the black people belong there.'  As opposed to asking oneself:  'why are these people willing to travel so far for minimum wage?', and the hundred other questions that scenario raises.  Obviously, the hardest to ask is : "Why am I comfortable with this?" or "Why don't I ask if this IS questionable?". 
The most insidious route this easy answer takes is conceptual.  Its much, much easier to think that all of any group a person might identify as a group by such readily and easily apparent attributes as relative skin tone are legitimately conceptualized of as one unit.  If this is the way a person thinks, then they can avoid thousands of dilemmas, questions, issues, and having to change their own preconceptions.  A person employing this paradigm might think "Well, those employees are at McDonalds because they are less capable.  They are less capable because their skin tone is much darker than mine."  It's easier to address societal issues that a person faces on a daily basis by conceptualizing society as comprised of a few  units (White, Immigrant, Religious, etc) than understanding that a society such as this one is comprised of billions of complicated individuals which contravene group incorporation merely by exisiting in reality.  The latter understanding is more difficult.  It's that simple.
Perhaps I could compact all this ideation into a few phrases:
"Racism continues to exist because its a shortcut to thinking and people are too lazy to take the long way."
However, in the end, the ability of the same people of the world to address this problem in discussion amongst themselves exists in the form it does today because of the sacrifice of other people like Mandela...and every person who thinks of him today or thinks of what his struggle meant--is a success for that struggle he fought for so long.