An anon yesterday pointed out that the counter was tracking accesses, maybe not unique visitors. They ran a script making 10,000 requests and the counter went up by 10,000.
So qmap.pub changed it to show the count over half an hour, but that clearly wasn't the best solution, kek. Not sure if that was unique visitors either.
It's actually quite a hard thing to get right without a lot of tracking help, cookies etc.
Website counters have always been BS, so I'm not sure what the right solution is frankly.
I haven't checked if they are using cookies, but I'd just add up session cookies and hope that it all averages out. Show the 24 hour total, and the users in the last half hour or whatever. Maybe set an Ajax callback to count browsers left open too…