We just published a great article about this in IDEA Trainer Success. Check it out here: http://www.ideafit.com/fitness-library/blogging-for-financial-success.
having a blog creates web presence. Since you determine the content, it is an opportunity to draw attention to what you have to say.
In addition to the blog that you can create here at IDEA FitnessConnect, there are other avenues out there. I use a tool from google, and here is a link http://www.blogger.com/home
The IDEA article is very informative and interesting. It is of particular value if your goal in blogging is to position yourself within your industry.
But, if you are ONLY doing it to promote your business, and you do not actively enjoy writing you may find it rather draining. There are tons of people blogging. If you are regurgitating the same advice it becomes like those fashion magazines that have had the same articles since I was a teen in the 70s: handy make up tips! cute shoes! low calorie meals! decadent desserts! (aside from the obvious problem with the last 2, does anyone remember that decadent actually originally meant rotten and bad?) treat yourself to long baths with candles! Find something you believe in deeply and say something from the heart in a way you hope will inform, or amuse, or motivate people.
I blog because I wanted a forum to explore more deeply some ideas that I do not have time to explore in the context of my classes. My intended audience is primarily my students, though I am happy to speak to anyone else who is interested. I love it when someone asks a question that leads to an idea that I hope will be of interest to others. Remember that blogging is not just about building your business…. it is about teaching, and connecting to others.