By clicking on the toolbar button, a TinyURL will be created for the page you are currently at. We've seen with new accounts it can take a few days to actually have data start populating in the MailChimp account. If you’re currently using classic Google Analytics, you need to update to Google Universal Analytics within your Google Universal Analytics account before you can set up tracking pixels with Eventbrite.
Not only is this good for link shortening, but it is also good for SEO. See if you are using Classic Analytics (ga.js) or Universal Analytics (analytics.js).