I actually use Joomla watch. As long as you publish the Joomla agent module it will give you some pretty accurate statistics about who is visiting your site, how many, and various other interesting facts. It's actually tells you in live time who is on your site and where they are browsing. The visitor module seems to be particularly accurate. Now correct me if I'm wrong, but it doesn't seem to register you more than once, in other words if you visit the page 3 times in 20 minutes, it doesn't seem to count you as a new visitor every time.
If you want a good "who is online" then I have been using mod_dwhoisonline and I reckon it's about as accurate as you are going to get.
Getclicky has the api to get the number of live visitors on your site if you are registered with them.
api.getclicky.com/help/api
This is pretty much what Joomla Watch does. You can also see where your members are browsing, the keyword used to find specific pages. The majority of statistics programs give you phrases and keywords that have been used, but they don't tell you which page comes up in the search.
I mean on the frontend whos online module, curl or something similar could be used to grab this number from getclicky to display the true number of visitors online: (note: site id and site keyare from the api pay)
I mean on the frontend whos online module, curl or something similar could be used to grab this number from getclicky to display the true number of visitors online: (note: site id and site keyare from the api pay)