Ads pay the bills for a lot of sites (including this one). But they can also be intrusive and with some of the tracking abilities available out there, a bit creepy. To combat some of that and to speed up page loads Apple introduced a Content Blocker feature for mobile Safari that allows third-party developers to create extensions that are "a fast and efficient way to block cookies, images, resources, pop-ups, and other content." Apparently people really hate advertisements on the internet because ad blockers have rocketed to the top of the paid app section of the App Store. But the side effect of at least a few of these apps is that it screws up shopping on the online versions of Sears and Walmart. Fortune talked to the developer of Crystal, an app that's messing with some shopping sites. After they informed him about what was happening, he said he would remove the sites from a blacklist. But, during our test, we were still unable to get to some product pages on Walmart.com to load. So, we decided to test some more online shops to how much commerce is being thwarted by a hatred of ads.