LONDON: Digital media agencies have warned that advertisers may baulk at spending money to appear on video-sharing website YouTube without more effective policing of user-generated material.

The site, owned by Google, plans to show viewers semi-transparent 'overlay' ads in its ongoing quest to turn an honest dollar.

But, says Rob Horler, MD of UK digital shop Diffiniti: "Advertisers will not write blank cheques to appear in clips they can't control."

Adds Jean-Paul Edwards, head of media futures at Manning Gottlieb OMD: "Brands have been put off by illegitimate content and unresolved rights issues."

Data sourced from Brand Republic (UK); additional content by WARC staff