I do not mind (sensible) spam in advertising-groups, it's what they're there for after all.
I just turn off notices, but leave one of the biggest cat-advert-groupchats open if I want to see what it going on.
-But spam in my IM is a 100% sure way to keep me AWAY from a shop / auction - I absolutely hate and detest it.
What I don't understand is that people keep making more advertising-groups. Why so many? Do we REALLY need more?
A couple of kitty-groups have 500+ members - and I have noticed that whatever is advertised in the other chats, is ALSO advertised in those... So why be a member of 10+ groups?