That's a tight subset, and I couldn't even guess what their browsing habits might be. However I could guess a savvy user has their firewall rules set sufficien

That's a tight subset, and I couldn't even guess what their browsing habits might be. However I could guess a savvy user has their firewall rules set sufficiently, disallowed a bunch of api scraping sites and may have installed additional safe browsing software. It might even include someone who's just got a good sense when a random link being dropped is bound to be full of nasties. The next question is, would they be spending much time on social media in the first place?