[adrianwaj]

I disagree. He's right. What investors should be asking is, "what is it about your idea, people and product" that is unique and difficult to replicate, whilst being crucial for your success. Typical barriers typically come via patents and strategic alliances. Who has those?

[sokoloff]

There are several other sources of barriers. Network effects is one; goodwill/brand is another; execution/operational excellence, etc.

Think about Ebay, Paypal, Facebook, Amazon. The vast majority of what they do is pretty far from rocket science. (By that, I mean a startup could create a technically credible competitor for their core business.) However, those companies have erected enormous barriers to entry in the form of network effects, brand/trust [of buyers], network effects, and brand/breadth/operational excellence.