While 23andme is a for-profit company, I think they will really accelerate genetic-based medicine. They will find many new insights into how people are predisposed to certain diseases, and ultimately open the door for better medical treatment. Once they've created their massive database, they can use their algorithms to find relations that regular academic researchers could not find due to time and cost constraints. I bet they're going to eventually become a very profitable company.
Take for instance certain genes that are known to cause cancer or other diseases with high probability -- I bet there are many more. They discuss specifically Parkinsons, who Sergey Brin has a 30-75% chance of getting according to stats (this will likely be narrowed down as they do more tests and find better correlations).