Vincent Baker, a renowned independent roleplaying game designer just posted this to his blog about getting your game played and talked about, and I think it's more broadly applicable than it first appears.
So with a little search & replace magic, just changing the word “game” to “product” and “play” into the more generic “use”, this advice is great for any kind of interactive product marketing.
So, your product makes promises, and then it delivers on them.
If you say “hey, check out my product!” and nobody does, that means that either (a) it's not making interesting promises, so nobody legitimately cares, or else (b) you haven't managed to communicate what it's promising yet, so you should keep trying. You'll have to figure out which.
If you say “hey, check out my product!” and people do, but they don't go on to use or talk about it, that means that it's not delivering on its promises. People were interested enough to check it out, but then the product left them cold.
From this point of view, getting your product used and talked about is a design problem. It's not enough to design a product that's technically usable, you have to design a product that provokes people into using it, and gives them things to talk about afterward. Not just a good experience, but a good experience with a highlight they can't wait to share, or a good experience with a troublesome spot they want help figuring out.
When people talk about getting “traction” in the marketplace, I think they are connecting to this idea. “Make an interesting promise and deliver on it” isn't rocket science, but sometimes the simplest ideas can get overlooked.