What you need to think about is that "e" has been used to denote a product or service marketed through or available on the Internet. As the Internet just becomes another common sales channel, the line will be increasingly blurred between online and offline marketing and sales, and "e" will no longer have a purpose. That is beginning to happen already. I believe that "e" dot com, net and org names are losing value daily and so when it comes to less established domain extensions, even one I strongly support like dot us, I don't think it makes a lot of sense in the long run to register or buy an "e" domain.