A tagline is a short phrase, slogan, or sentence that communicates the essence of your company. A tagline can be practical, simple, metaphorical, dramatic, etc. There are general rules and best practices marketers and copywriters follow, but taglines do indeed vary a lot company to company.
A company might have more than one tagline to use for different purposes and often companies will change their taglines many times over the life of the business.
Amplify Your Online Voice. (PowerUp Productions)
Just do it. (Nike)
Think Different. (Apple)
The Ultimate Driving Machine. (BMW)
For example, we currently use “Web Design & Branding – Boulder, Colorado” as our WordPress tagline that shows up in Google and at the top of a person’s browser. But we use “Amplify Your Online Voice” for our general marketing tagline, along with a few others we like.