While we do not limit the number of visitors that can view your website, we do limit the number of visitors who can simultaneously connect to your hosting account. There’s a subtle difference there because users only count as “connecting” while they’re actively downloading content from your website.
However, as soon as users finish loading a page’s content or disconnect from SSH, their connections are freed up for other users. This means if the page a user’s connecting to takes .1 seconds to fully load, she only counts as a connection for .1 seconds. After that, she no longer counts toward your total allowed connections — unless she clicks somewhere on your site that establishes another connection.
This means, theoretically, a very large number of visitors could be viewing your website at the same time, as long as they didn’t all process the requests simultaneously.