The only information actually stored is the email, from Google sign in, and an approximate location for the map feature, if you enable it. This allows you to see a world map of votes, what opinions are present in what places.
The intent is to catalog the world's opinions, organizing people's public thoughts so they're easy to sift through. This data can be extremely valuable, whether it's political polling, information about people's preferences, trends over time, and so on. Many people could benefit from this, and it's meant as a public service, to lift the veil on what people think about any topic, at any time. Easier political polling is just one obvious application of this.
Please try it out and give any feedback, thoughts, questions, and so on, here or within the profile section on the website, which is fully anonymous. Thanks.