What do you guys think of Mixmax? Heard of people liking their service for making appointments within Gmail, and e.g. receiving read receipts. From their privacy policy:

> [...] Mixmax may securely access or store your name, your Gmail email address, your Gmail emails and other conversations, and your Gmail contact list [...] We may anonymize your Personal Information so that you are not individually identified, and provide that information to our partners.

https://mixmax.com/privacy.html https://mixpanel.com/privacy/