I used to use the circus as a device to explain marketing to people.  Here’s marketing by way of the Big Top. 

When the circus comes to town, the advance man buys a billboard that says “The circus is coming!”  The billboard usually lists the dates and shows a picture of an elephant.  This is “advertising”.  You pay for it and you have complete control over the ad’s content.

When the circus arrives in town, they usually parade the elephants through town.  This is an “event” or “promotion”.  The TV cameras show up and capture the event — this is “coverage”.  People come out of the houses to watch the elephants and everyone knows the circus is in town.

However, if one of the elephants escape and tramples the mayor’s rose garden before he is caught, this is “news”.

If you get the mayor to smile for the media’s cameras, get his picture taken with the elephant and say, “What’s one or two rose bushes between friends?  Everybody loves the circus!”  Now that’s “PR” with an emphasis on media relations and a nod to “influencer relations” or “government relations”.

Today, the circus has a Facebook fan page, several of the performers have Twitter accounts, the ringmaster blogs, there’s a LinkedIn group for jugglers and everyone posts their favorite picture of the elephants on Flickr.  The best images show up on Digg or get Stumbled.  This is social media, and to my way of thinking, it is still PR.  PR=Public relations.