Q: I want you to develop a clone of site X for me. Can you do that?
A: When you send us specifications, please do not say "I want a clone of site X".
If you want a short answer to the above question, then it is most likely: "No".
The long answer is "it depends".
A reference site, or screen shot can be a very helpful way to visualize what is needed, but should not be the only way to describe your project needs.
Your requirements have to be in bullet points and/or headings and paragraphs. These discrete function points are what really matter when scoping a project initially.
By all means, use a reference site (or screen shots, wireframes, ...etc.) to clarify what you mean, but you also have to have some paragraphs to describe what you mean.
Moreover, it is often the case that certain functions are all that is needed from site X. It is impossible for use to narrow down what you really want from an array of features available on that site.
If it is hard for you to describe what you want, then it is harder for us to develop it.
So, please be specific and concise, and only use Site X as a clarification tool, and not the only functional description.