Recently I was browsing a well known British high street shop's webshop and in the middle of my session a pop up appeared asking if I had any comments on the site. From a recent survey I did on mobile apps I know that 47% of people would uninstall an app that had a pop up that asked for feedback. Is there any evidence that web users are more forgiving about this sort of pop up?
Any popup not initiated by the user is intrusive and will likely annoy them.
This seems especially bad for a storefront. Delaying someone from being able to research, compare, and potentially purchase items is not good for them nor the business. The interface supposed to help someone reach a goal, not distract them.
Actual browser-window popups were so annoying to people that every browser started including a popup blocker. Today, this practice is coming back in the form of modals/lightboxes that come up automatically and is equally as annoying.
In the case of an online store, the customer could be prompted for feedback after they have completed their purchase, instead of beforehand. Their feedback would probably be more useful at this time anyway, since they had actually completed the entire process of finding and purchasing something. It shouldn't be done with a modal window, though, but instead as an aside somewhere like their order confirmation page. "Thanks for your purchase. [Order details]. Earn a $5.00 credit by sharing your experience with us today." for example.
Amazon sends emails about shopping experiences days after the product is received. Sometimes they ask for you to review the product, and other times they're curious about how the packaging of the product was. It's non-intrusive, and I personally don't mind getting the emails at all, unlike how I'd feel about a popup window while I'm trying to shop :-)
In my experience at a previous start up, we found that pop-ups like this were a bad user experience, but they did yield more feedback than a normal feedback form. It's up to every business to decide whether the extra feedback is worth the reduced visitor satisfaction.
However, a slightly modified idea, which is making live chat available, but not using a pop-up was very helpful for everyone involved. People love to chat instead of writing emails or calling, but as we grew the load on our customer service operation was just more than we wanted to dedicate to the project.
Like others have mentioned, popups are annoying for a lot of users, they interrupt the browsing experience and hinder users from reaching their end goal.
In this instance the concept of using a popup during a user's visit to a site to evaluate their experince seems absurd. Surely this should happen at the end of a user journey (possibly after a purchase) or when a user decides they want to mention an issue/give feedback.
I've seen this service (https://www.uservoice.com/) used on a few sites. It inserts a tab on the side of the page which a user can click to give feedback on the site. Its not the most attractive solution but I like it. You can see it in action at the http://www.php.net beta site.