I see a lot of companies struggle with email surveys. Some email providers have tried to embed forms into their applications, only to find out that most email clients (online and off) won't render the email survey properly. Unfortunately, email is often best designed when it fits the capabilities of the worst email client.
Since email clients do offer the opportunity to click on links, the easiest way to capture a simple poll or survey via email is by including separate links for each answer. I just received a Netflix email that does just that:
Nice and simple. No login was necessary (an identifier was included in the link and passed to the destination page that counts the survey), no clicking a link and then opening another form, no entering data…. just a click. That's a powerful click! I'm not sure why more marketers (and more email service providers) don't use this methodology!