Founders like to talk about "focus" a lot, but when it comes to creating focused brand messaging many find that it's actually a more frustrating and challenging experience than they expected. The reality is that you face a struggle between two conflicting instincts: the need to clearly and narrowly define what your company does; and the desire to paint a compelling, expansive, and inspiring picture of what you envision your company will become.
By definition, using focused and definitive language is an exclusionary act. If you say you build accounting software for SMB's you'll worry you might be in trouble when pitching a Fortune 500 contract. If you say you're a web shop experienced in building e-commerce sites, you are concerned that you'll have trouble with your dream of building a media website. And so on.
I used the terms "need" and "desire" for a reason however. You may want to paint the most broad and rosy picture of your business, but in order to succeed with brand messaging you absolutely must be able to communicate quickly and simply what kind of thing you are.
And let's face it, people know how to read past vagueness. So don't tell people you're a leading transportation logistics company if you're a taxi service, or that you're an mobile events food provider if you're a hot dog cart. People like taxis and hot dogs, and they might like you.
For an excellent example, here's an excerpt on focus from Netflix's investor relations page:
Netflix is a global Internet TV network offering movies and TV series commercial-free, with unlimited viewing on any Internet-connected screen for an affordable no-commitment monthly fee.
We don’t and can’t compete on breadth of entertainment with Comcast, Sky, Amazon, Apple, Microsoft, Sony, or Google. For us to be hugely successful we have to be a focused passion brand. Starbucks, not 7-Eleven. Southwest, not United. HBO, not Dish.
We don’t offer pay-per-view or ad-supported content. Those are fine business models that other firms do well. We are about flat fee unlimited viewing commercial-free.
We are not a generic “video” company that streams all types of video such as news, user-generated, sports, porn, music video, or reality. We are a movie and TV series entertainment network.
Remember, if it's not immediately clear what you are not, then nobody is going to ever know what you actually are.