The Google+ Polls feature has been around since October of last year and although much of the novelty has worn off since then, it remains a nimble tool for viewing people's views in an easy to read graph without much effort for the one asking a question, and for those answering.
It is easy to lose track on what you've previously voted on, so thanks to an update which has recently rolled out to Google+ settings on the desktop, you can view each individual poll you've voted on in a convenient list, and if you want to view a specific poll to change your vote, that's possible too.
Viewing your votes
To take a peek at your votes, make sure you're using the Google+ desktop site. Go to settings by opening the navigation menu on the left and clicking on "Settings". Scroll down until you see the "Apps & activities" header and then click on the "Manage votes" button.
Alternatively, enter plus.google.com/polls/votes into your browser's address bar to take you straight there.