It's as if the internet were a giant cable TV line-up or magazine and the consumer will be clicking through it, land on the microsite and magically become entranced.
This delusion is leftover from pre-internet days when people would indeed be flipping through a magazine and an entertaining and eye-catching advertisement was the only way to grab their attention. It's become so firmly embedded in the belief system of most agencies as to be virtually instinctual. But it's a bad habit we desperately need to break.
People only go to your website for a reason. And they go there on purpose, not by accident. The website has to provide them with some manner of utility. Now, "utility" can take on many forms. It can mean a site like Nike+ or Domino's Build-A-Pizza that lets you do something useful, or even some sort of fun and unusual game of the sort that I can't find in a superior form, unbranded, elsewhere on the web.
So that's step one. Step two is actually promoting the site. You see, again, most marketers and their agencies make the mistake of assuming that their customers are clairvoyant, and will immediately intuit that they've built a special microsite. You know what? They're not.