I don't mind/care if they're promoting it.
But I dislike when they're not upfront about it.
eta: btw, there are rules for people promoting their businesses on this site.
http://www.quiltingboard.com/t-99668-1.htm#2702773
"in other words, are you a genuine board member who just happens to also own a business?"
Hardly.
But the fact that someone is trying to engage me in a conversation about how "great" this product is without full disclosure - that ain't cool in any venue.