The online ad industry is rallying to fight piracy, fraud, extremists and fake news. Does it stand a chance?

A technology company wanted its ads in front of people reading online about data storage. Instead, tens of thousands of dollars worth of ads landed on websites that belonged in the Internet's trash can. There was clouddatarecoverywebhost.info, where the firm's ad appeared on a page that featured a viral YouTube video of a woman whacking an attacker to the ground with a dog. Aside from their URLs, the websites had nothing to do with online storage. In the tangled ecosystem that is online advertising, such nefarious websites collectively reap billions of dollars annually bilking advertisers.