Definition:  an interesting article, telling a compelling story, which also serves to promote your product or service.  Why an advertorial?  Advertorials are typically paid for, so if you are struggling to get free press coverage in the right journal/magazine, this can be a way to get around the problem.  It’s imperative that you have a good story, though – no one will read an article that does nothing but sell, sell, sell.  Think about what you would want to read, and then try to create something which reflects this.  Decide what you want to promote (your entire service/product portfolio, a specific product, or perhaps just your brand, business and staff), find the story that fits the sell, start and finish the advertorial with the story (not the sell), use quotes, avoid slogans and clichés, and include contact details, but no prices.