They might be growing by a decent percent but I doubt Overstock will ever be a threat to them. What is their actual revenue compared to Amazon's though?
Revenues are far off. For Overstock it is only about $1.3 billion per year. Amazon is having revenues of around $75 billion. Not impossible to catch up, but far way off.

Yeah, thought as much. Suddenly that 30% growth doesn't seem that much compared to Amazon, but I wish them all the best. I really admire their CEO and even more-so after he got his company to accept BTC.