Not exactly a thread about a thread - more a thread about lots of threads.
We so often see the advice from contributors on here that you shouldn't feed a cat you see hanging around, even if it looks hungry, as it might have owners. Well yes, it might have owners, but it might also be stray/abandoned/starving and if no one feeds it then it will end up like this rescue I was called to yesterday:
www.facebook.com/celiahammondanimaltrust/posts/830773006933560
When looking for this cat I went knocking on lots of doors and most people had said that yes, they had seen a very thin, desperate looking cat hanging around for the last couple of months. When I asked if anyone had fed it most just shrugged and said no as 'it was nothing to do with them' (fair enough - you can't make people care), however a couple of nice people said no, they hadn't wanted to as they were worried it might belong to someone. So that cat was slowly dying of starvation as a result.
So, if you're worried about a cat, please do feed it. Then to check if it has an owner use a paper collar, or get it scanned for a chip (for free) at any vet.