The word Guru is a Sanskrit term that means someone who is a teacher, guide or an expert in a particular field.
For experts in their fields
A knowledge, idea or innovation not passed on is dies with the inventor. Be the guru the world need in your profession or hobby and teach people. And teaching people has become very easy with the advancement of the internet. You are no longer limited to a singular spot. You can teach thousands of people from the comfort of your home. You are no longer limited to a singular spot. You can teach thousands of people from the comfort of your laptop and a well designed website. And if you are really that good at what you do, a .GURU domain name should perfectly fit into the general aura of your web presence.
For marketing purpose
People tend to be drawn in by words such as NINJA or GURU when they are making a sell improvement purchase. As a marketer you must have being taught that presentation is everything. If you book, software or any product you are selling is really good. Why not attach the word guru to such a thing when you buy a .GURU extension for the website? That way you get to attract more sales through the site.
For spiritual centers
When an average person hears the word guru, what comes to mind is something spiritual. Why not capitalize on that for your spiritual center by buying a .GURU domain name for such center website.