Google is cracking down on mobile pop-up ads

Websites with mobile pop-up ads, watch out. Google is cracking down on the "intrusive" advertising by knocking down those pages in its search results, the company said Tuesday. 
Any website that shows a pop-up ad that covers the site's main content — whether right when the user gets to that page or while the user is on the page — will be ranked lower in Google's search results. That applies to pop-ups users have to dismiss to continue onto a site, and advertisements that cover t