The voice a business uses in its writing says a lot about both the company and its customers.
Just as you typically wouldn't yell in a business meeting or talk politics during Thanksgiving, you shouldn't let the characteristics of your content stray from the spirit of your company. This is why both marketing writers and journalists must take the time to understand not just what they are talking about, but who they are speaking to/for.
A caring nursing home hoping to engage patients who need support would likely choose an amiable, compassionate tone. Strong, confident language would suit a serious law firm looking for respected clients. The website of a fun party supply store would probably want to attempt to match the liveliness of kids filled with the endless sugar and fun of birthday cake.
Whatever voice makes sense for you, keep in mind that it's all a part of your unique style.