Are there really 800 plus guests viewing this site at this moment?
The number on the index page below "Users Online" always refers to the time frame set for that in the control panel. For this forum it is set to 24 hours. You can see from what it says there right now : "392 Guests, 9 Users Users active in past 1440 minutes". That means in the last 24 hours visitors from 401 different IP addresses (+ 51 spiders/search engines shown to me only) have visited this forum. The other forum for example has set this to 15 minutes. So there you can see how many different IPs have visited in the last 15 minutes. If it says there 10 for example that does not mean in the last hour 40 had visited, or that in the last 24 hours 960 had visited, because they could have been the same 10 only that did connect in the last 15 minutes. There is no further counting and differentiation. I prefer to know how many look up this forum in a day instead of 15 minutes only.
When you look up services like Alexa you can see how many visitors who have installed Alexa toolbar in their browser did connect to certain domains. That gives you a faint idea for comparison.
For the last month these comparative numbers of "Reach" are shown there for the Korat forums (in parenthesis difference to one month ago):
0.00072 (+40%) for korat-info.com (German forum, no Alexa toolbar in German available, actual value should be higher)
0.00076 (+5%) for koratfart.com
0.00065 (
-20%) for koratfarang.com
0.00057 (+40%) for grumpyexpat.com
0.00039 (+30%) for isaan.com
0.00015 +600% for korat-farang.com (still new)
Now I hope DD doesn't rant about the restriction of the Alexa values again; I do know they're only good for webmasters and to give them only a faint idea about their site's performance in relation to other sites.
If you want precise and reliable figures all admins would need to run the same statistics software and openly reveal the results. Don't count on that!