Why does Google Analytics real-time show more visitors?
Google's Real-time Analytics uses a different method of detecting how many people are on your website, which is why Olark shows different numbers of visitors.
How Olark counts visitors
When a visitor enters your website, Olark starts pinging its servers every couple of seconds to see what they are doing on any given page. We know to within a second when your visitors enter and leave a website.
How Google counts visitors
Google's real-time stats counts new page views as visitor activity, checking every 5 minutes or so to see if the visitor is still online. So if a visitor leaves immediately, Google real-time won't know for 5 minutes. Similarly, if a visitor stays on one page for 5 minutes, Google will assume they left your site.
What else can affect visitor numbers?
Some of your users may be using mobile devices, check if you have the Olark mobile theme enabled in your Appearance Settings
You may have more visitors than you have slots on your list (which is currently ten times the number of allowed agents), which means that some of them won't show. We do some tricks to prioritize who gets a slot on your buddy list, which are based on some API actions and activity.
Rest assured that those visitors have no problem seeing your chat, and will be able to initiate conversations with you, even if they don't show on your buddy list. If you use Targeted Chat rules, visitors that you update nicknames and status on will get priority slots in your list.
Some browser ad-block extensions or parental control programs have secondary lists that include chat apps. There's nothing we can really do in that case--the customer has taken the time to opt out of chat by installing that service, and the nature of the web doesn't allow us to override that preference.
The visitor may be able to whitelist Olark as an acceptable application within the settings for that service.
Olark does not show idle visitors in the buddy list after approximately 2 hours. If a visitor is sitting idle on your site, meaning that they are viewing the same page and have not sent any messages through Olark, then we stop showing them in the buddy list after about 2 hours of idleness.