Hello Jason,

I believe it's because these sessions are not cleared on the site for some reasons (I probably do think that Joomla wasn't able to clear the sessions table) because of cache. You can clear off all records in jos_sessions table

How?

Mark I deleted the cache of Joomla, hosting and jos_sesions table and still shows many members online.
In analytics shows me only 2 members online and in the forum and joomla 126. Modulus users online also.

Hello Jason,

Hm, I checked your site and it looks like the #__session table has 16k records and it wasn't cleared yet. http://screencast.com/t/F9hcED7cr

Hello Mark
I deleted the table and now it's fine. Is there any way to fix this?

Hello jason,

To be honest, everyone that enables this cache would seem to hit a pretty similar issue

Mark
I recommend not using any cache?

You could also set a lower session live time in the global configuration area so that Joomla would be able to clear these data but to be honest, I am not really sure why Joomla isn't clearing these sessions.