Polls are a fun way to speed rate groups of topics, which will improve your Similarity Network, as well as compare your interests with other Lunchers. It's also a great place to find review inspiration.
To start, hover over the "Explore" button on the top of the homepage page on the side and click on "Polls" in the drop down menu. From there, you can select a poll that is of interest to you and rate away. You can also access Polls from the "More" tab at the top of of any page in Communities on Lunch.