Stack Exchange isn't a social network, it's a Q&A site. There is no value to knowing that
user53168 visited your profile as you cannot contact them or do anything of value with that information.
Also, voting is anonymous, so there is no way to know who has voted. Again, there is no benefit to knowing this, there are only negatives ("oh,
user76436 voted for my answer so I better vote for something of theirs too incase they think I don't like them"...)
The site focuses on, and revolves around Questions and Answers, not individual users activity, so yeah, let's leave LinkedIn to do what they're good at and stick with what works well here.