Facebook for Developers has a “Was this document?” button stuck at the button-right of the page. You can select “Yes”, “Yes, but…”, and “No.”

When you select “Yes” a confirmation appears to thank you for your feedback:

Thank you for your feedback.

When you select “Yes, but…”, a modal appears with several checkbox categories and a text area to send comments:

How can we make the document more helpful?

When you select “No”, the same modal as the “Yes, but…” response appears but with slightly different leading text:

What can we change to improve your experience?

If you close the feedback feature, a “Give Feedback” button appears.

Give Feedback.