In many of your classes - particularly your portfolio courses - you'll hear the term "branding" come up. At first you may ask yourself, "What's all this nonsense about branding"? Well, it has to do with your choices: the choice you make when you pick the font that goes on your website, the color, your logo, the layout of your site... mainly, your attention to detail and ability to produce a "complete experience" to the client as they wander through your website and portfolio. Branding also has to do with the sub-genre of photography that you shoot. For example, Haisch is focused on "Retail Photography" - more specifically: weddings and all the other types of photo shoots that relate to weddings. Your branding also has to do with the consistency of your style of editing.
By no means does this "pigeon hole" him to only shoot weddings 24/7... If you visit his website, you'll also notice that he has a section titled "Personal" - aka - shoots that have nothing to do with weddings. (That's how you can "sneak in" your other photo shoots on your site that do not necessarily fit into the sub-genre you're focusing on for your business.)