When you start approaching your visitor or company lookup quotas, we start sending you reminders in the app and via email when you start approaching your quota.
When you exceed your quota, we pause any new personalizations made to anonymous visitors, and we keep personalizing your website to visitors that already belong to a personalized segment.
In short, we continue personalizations for returning visitors, but don't personalize any new visitors.
If you have exceeded your quota, it's still possible to change your segmenting rules and personalize your website to visitors that have already been personalized once, ie returning visitors.
You can check your usage under the Usage tab in the app.