How to get there: Go to Settings → General → toggle Search engine indexing.
By default, public ProductLift portals are indexable so customer feedback shows up in Google. If you don't want that, turn it off.
When Search engine indexing is disabled, ProductLift adds a noindex, nofollow meta tag to all portal pages. Google and other crawlers respect it and drop your pages from their index (or never add them in the first place).
This is a soft block. The pages are still reachable by URL. For a hard block, combine with Restrict access to your portal.
The knowledge base has its own indexing setting since SEO is often desired for KB articles even when the feedback portal isn't. See Knowledge base SEO.
If your portal was indexed and you now want pages out of Google: