Semi related articles on site

Hi,

I have a domain selling site called: Namecake.com. I have domain related articles on there and will shortly be adding 50 more articles.
I was thinking about adding Logo, Business, advertising, PR articles as well.
All of the topics have good search results but little competition within Google (a few hundred thousand pages listed.)
Is this a good idea - will the SE's just look at the keywords and the text or at the wider site and say, "this doesn't fit in here." And chuck me at the back of the search results.

Any advice would be greatly appreciated.

Thanks