Ask HN: Most effective way to provide feedback on Google instant search?

I've previously attempted various means for providing feedback on Google's search interface and it seems to fall on deaf ears. One bad sign is that they don't have any feedback link on the page. But I just found out that if you enter a query into the instant search, and give it a few seconds, it retains that search query in the title of the page and tab, even if you erase the query and there are no results. This seems like unwanted functionality (a bug), but I would really like to use the proper channel to provide this feedback. Does anyone know the best way to get Google to pay attention about issues with their main search web interface?