If you're receiving the message below (or similar), the issue is most likely related to the version of the extension you are using:
"The Bananatag extension for Gmail (for false) was unable to load the jQuery library. The extension has not been initialized. Try restarting your browser."
On occasion, Google changes aspects of how Gmail looks or how it is loaded. These changes can cause the Bananatag extension to have an error.
We release updates to the extension as soon as we are able to detect a change in Gmail. If you are using Chrome, updates to the extension are automatic (may require a forced refresh), and if you are using Firefox, you’ll should ensure you've download the newest version of the extension.