It is a good idea, due to the increasing number of virtual world services, getting a good customer service from live person is becoming a rare thing. If you are specialized/experienced in an industry, I suggest that would be the starting point for your customer service desk. Please note that, customer service is all about "providing right information, make a sale, solve a problem". Certainly you can provide a customer service which includes all the above three components or one component.
You must also look into the existing customer service companies, a.k.a your competitors. Do a research on their business and revenue model, number of competitors in your industry, geography, profit margin, which will give you an idea whether you can make a living out of it. However, you need to differentiate yourself from your competitors which is the key to make money. Hope it helps.
All the best