Signing you in, remembering what is in a form you are filling, and blocking abuse. The site cannot work without these, so they cannot be switched off.

Google reCAPTCHA on the sign-in, sign-up and RSVP forms, which tells a person apart from an automated attack. With this off nothing is sent to Google and the forms still work — they are rate limited instead, so a handful of attempts from one connection in fifteen minutes.

Loading a Google map on a listing page. With this off, the page shows a link to open directions in your own maps app instead.

Counting which listings are viewed and which contact buttons are used, so business owners can see how their listing is doing. No IP address and no browser fingerprint is recorded, and nothing is shared with an advertising network.