I don't handle myself ANY personal or sensitive data from my extension's users.
Your email, payment info, etc. is directly handled by Google's Chrome Web Store and they're responsible for managing your data. I don't know who paid for the extension, just receive a generic order where the only information I know about my customers is city, zip code and country. Google handles those data and keeps them safe.
NONE of your personal data or activity on the internet is transmitted to any server managed by me. They never leave your computer, except the information stated in the next point.
Only ANONYMOUS info about events you do through the extension (times an ad is clicked, for example) is sent to Google Analytics for statistical purposes, to better understand what users do and, then, improve the extension. Those events are NEVER related to you in any way. Only the global numbers are saved.
Anyway, NONE of this information will be ever sold, given or transmitted to anyone else and its security is warranted by Google.