SitePoint uses Survey Monkey for its surveys. However, I don't know how that would attract the new views you are looking for. You might consider posting a request to view your site on a Social Media platform and indicate you are looking for new viewers only, but that would be a hit and miss as well. Additionally, I see a lot of sites have a squeeze page that asks the viewer to take a survey. Depending on your present traffic flow, that might be the quickest ... or the longest method of getting what you want. Keep in mind, too, that squeeze pages often leave a bad taste in the mouths of visitors. I know I hate them. You probably don't want the first impression your site makes to be a negative one.