Polls are a very simple way to engage audiences online. By making readers interact with your online content, it allows them to share their views in a more visual way.
I think polls also help journalists do their jobs. This is due to the ability to ask readers what they are interested in and what topics they think should be raised. Therefore, by finding out what content audiences want it allows you to sustain and build them.
Below is a poll I created using Poll Daddy, which is really basic.