Hiding the pin collections and pin reviews doesn't bother me. It's their preference. But for those that do share that info, I can tell if I should value their opinion. If someone has all EM's and rates all of the new pins (in general) really low, then they have a different pinball interest than me - not that there is anything wrong with that. Others that have similar types of pins and rate pins similar to me, I do value their opinions more than others. The typical trolls and thread bullies usually don't show their collection so that they don't have to get defensive about it. You will see that often.
I only had one person ask if one of my pins was for sale - 2 months after I got it and wasn't ready to part with it yet. I haven't sold a pin yet ... guess I'm currently still a pinball hoarder. I got room for two more, then I will need to sell one to buy one.