Users have the option of flagging Magpie tweets as ads using a special tag. (Twitter)

An ad network that lets users profit from Twitter is making it harder to distinguish between autobiography and advertising on the social networking site.

"It's a shame," said David Silverberg, editor of DigitalJournal.com, about the Magpie advertising network. "It starts to make people feel like they can't trust who they're following on Twitter."

Twitter lets users send tweets, brief updates of up to 140 characters, to their friends or "followers" about their daily lives.

Farhan Thawar, a Toronto software architect and avid Twitter user, thinks the network is handy when, for example, you want to pick a restaurant for dinner. You can send a tweet asking for suggestions and can expect locally relevant responses from your trusted friends.

Twitter allows users to seek instant advice from trusted friends, says user Farhan Thawar. (CBC)

"And then later on they'll say, 'How was it?'" he told CBC News Sunday.

Magpie, which is headquartered in Berlin, pays Twitter users for allowing it to send tweets from their accounts promoting the products of companies who have subscribed to the service, such as Expedia's New York travel specials and Apple's iTV.

Many appear to have been designed to look like real tweets. They include a shortened link to the advertiser's website and sometimes a statement like "got mine couple months ago. love it!!!" or "going skiing next week" that resembles an update about the user's life.

Users pre-approve ads

However, the service allows users to flag tweets from Magpie as ads using a special "#magpie" tag. It also allows users to pre-approve all Magpie tweets from their account.

Jan Schulz-Hofen, the head of Magpie, told The Canadian Press that more than 1,000 companies use the service, including about 50 Canadian companies. He added that about 80,000 of the two million people who follow Magpie users on Twitter are Canadian.

Farhan Thawar said he's noticed that people tend to "un-follow" those who send Magpie tweets from their Twitter accounts. (CBC)

Users are paid based on:

• The number of followers they have.
• The number of adver-tweets they're willing to have sent from their accounts compared with real tweets.
• Whether they choose to get paid per view, per click, per sale, or for each query about an advertised product or service.

However, they have to make a minimum amount of 50 euros ($80 Cdn) before they can receive their first payment.

Thawar, who has about 500 followers, would be able to make up to 144 euros or $230 a month from the service, but he's not buying into the concept.

"Is it worth the reputation that I would get from just posting ads that may not be relevant to my friends?" Thawar added he's noticed that if someone has Magpie tweets on their Twitter accounts, others will "un-follow" them.

Silverberg said he thinks the rise of Magpie is too bad.

"Because people really want an authentic voice, a real person behind each Twitter account," he said.

Many companies were criticized after their Magpie tweets were republished on the website ReadWriteWeb earlier in April. Some, such as Apple, have since responded that the ads were produced by outside affiliates.

With files from The Canadian Press