PDFs are Evil, Lazy, Slothful and Sinful: Nice rant here, and a pretty good point. PDFs should be for stuff that is meant to be printed or be otherwise portable. If not, then it goes in HTML.
The Web is not print. What may work exceptionally well in print may fail miserably on the Web. Print marketing material is designed to get attention. It is written with the intention that the customer will read it in some external environment. Therefore, it often contains contextual and background information on the organization.
If someone comes to your website it means that you have already got their attention. Your print brochure, or whatever other form of marketing you used, has worked. The worst thing you can do now is keep using tactics for getting the attention of someone whose attention you already have.