"Google Feedback lets you send Google suggestions about our products. We welcome problem reports, feature ideas and general comments," informs Google.
To try Google Feedback, go to Gmail, click the "settings" menu and then "report a bug". A similar feature is available in Google Docs, YouTube and many other Google services. You can see the old version of Google Feedback if you click "Report a bug" in YouTube's footer when you watch a video.
Google Feedback started as an extension and now it's a web app.
{ Thanks, Sterling. }