I struggle with the same issues. My main clients are kids with ponies. Though, I just did a show breeder and her whippets. Yes, the photos are advertising on her site, but, in the same breath, those photos are advertising for ME. I ask for a link back and credit. I know this has worked so far for me, as that is how I got her as a client.

I am fairly new as a photographer. So, my needs are different than those that have been in it for 20 years and are already known. The more people see my name, the more "validity" I get as a photographer.

I have personally drawn the line on advertising as sending a high rez file to a magazine. I am probably wrong though.