Is Facebook advertising worth the investment?

While brands and advertisers have flocked to Facebook to promote their wares and connect with consumers, the jury's still out on the true value of the site for marketing.

The BBC recently completed an investigation into the effectiveness of the social network as a promotional tool. Running a campaign for a fictitious business called VirtualBagel, BBC technology correspondent Rory Cellan-Jones spent $10 advertising the company's Facebook page.

At the time of writing, the company's page -- which contains only an image of a bagel and the address Ealing, London -- has amassed 3,113 "likes" on Facebook.

The BBC found that the number of "likes" in countries such as Egypt and the Philippines was out of proportion to the countries the virtual company targeted, such as the U.S. and U.K.

Michael Tinmouth, a social media marketing consultant who runs online advertising campaigns for small and medium-size businesses, told the BBC that Facebook's targeting system may not be up to scratch. In Tinmouth's experience, when companies targeted global audiences, the majority of responses came from particular areas. He said:

"They were 13 to 17 years old, the profile names were highly suspicious, and when we dug deeper a number of these profiles were liking 3,000, 4,000, even 5,000 pages."

When his customers began to lodge complaints, the consultant contacted Facebook, but was told that the majority were authentic and no refunds would be issued.

In response to the investigation, Facebook told the BBC:

"This doesn't represent the experience of most advertisers on Facebook. The examples that you have mentioned are really unusual and seem to be the result of some bad advertising practice.

Looking at the test case you flagged - the person has, for some reason, taken a scatter-gun approach to distributing their ads, sending them to multiple countries with little or no demographer targeting.

Facebook's Page Insights service is designed to help marketers keep track of who "likes" their clients. In the real world, if you hand out flyers for a pizza restaurant in Birmingham to people in Beijing and Mexico City, then you're not going to get the customers you want. The same applies to online advertising."

Cellan-Jones also discovered that a number of the accounts that "liked" VirtualBagel did not seem to be genuine.

Earlier this year, the social network estimated that 5 percent to 6 percent of accounts created on the site may be fake, which would result in up to 50 million profiles.

A spokesman for Facebook told the BBC, however: "We don't see evidence of a 'wave of likes' coming from fake users or 'obsessive clickers'."