Numerous sites have started utilizing different methods to force you to disable adblock or pay for an 'ad lite' version of their site. Until you do either, you'll be presented with an overlay above the content and scrolling will be disabled on the page.
'Overflow' is your tool against that! When you come across a site that uses these methods, simply click the Overflow icon in the Chrome toolbar, and then click 'Add site to blacklist' after the site has loaded completely and the extension will attempt to restore scrolling and remove the overlay. This will also be remembered for the next time that you visit the site!
It may result in a less-than-ideal experience as it is designed to fix many of the most prevalent methods used by these sites. If a site becomes unusable, then simply click the Overflow icon in the Chrome toolbar, and then click 'Remove site from blacklist' and reload the website.