The product or the sales team?
I tend to be a big believer in the idea that the biggest contributor to a product’s (or service’s) success is, quite simply, its quality.
In other words, it’s kind of an “if you build it, they will come” scenario when you’re making something to sell.
But I bet there are a fair number of good products that never took off like they probably should have. Some of them were probably even marketed fairly well.
I think the key to having a “viral” product (for lack of a better term) is to have a product that makes people want to recommend it.
There’s some elusive line between something that is merely good and something that makes you want to share it. Every one has, at one time or another, found a product or a service that they insist other people try out. That’s the sweet spot.