user6841: I don't think USB chip is more expensive than Ethernet chip. So, I expect there should exist a board like Arduino, but where USB is removed in favour of Ethernet.
Are there such boards?

user4909: Yes, there's the Arduino Ethernet. Available from Sparkfun for example

6841: <p>I don't think USB chip is more expensive than Ethernet chip. So, I expect there should exist a board like Arduino, but where USB is removed in favour of Ethernet.</p>

<p>Are there such boards?</p>
 4909: <p>Yes, there's the Arduino Ethernet. Available from <a href="https://www.sparkfun.com/products/11229" rel="nofollow">Sparkfun</a> for example</p>
