I'm a freelance writer as my main job and running authority sites on the side. I have been intending to get into a specific niche and working on ideas and a site. However, about three months ago I began writing articles for a client in that niche. I still want to get into it as i have experience in this niche and enjoy it. But, I'm wondering if there is an ethical issue writing articles for a client while building a website in the same niche. Obviously, the articles I write for my own site will be different. Any thoughts on the matter?