This is one of those questions that make people squeamish. Probably for good reason. Not a good idea to draw attention from cops or criminals.
It is a little odd, though. We post on a gun discussion forum so it figures we all own some guns. Most of us post photos and discuss various guns we own so obviously some members have quite a few guns. But when asked for a specific number we get cold feet. Me included. Not sure why.
You can count on some members of these forums having very large collections. You know serious collectors (3 or 4 names on this forum leap to mind) who regularly post photos of fabulous, rare and extremely valuable guns. Where's the guy who recently posted he had 450 guns including numerous machine guns? That is a valuable collection. I know a guy on another forum who posted photos of about 50 Winchester Model 21 shotguns he owns. These things routinely sell for a couple grand apiece. And it's not like that's all he owns.
I was invited to man's house one time so he could look at a pistol I had. I can only guess at the number of guns I saw in his home. There were guns everywhere. Stacked in corners, laying in piles on the floor. I was stunned. I think at least a thousand guns were laying around in the open. He also had a large gun room and I think he had outside storage, too. To me, he's a god.
But again, most folks blanch at a direct inquiry.