On the heels of its Promoted Tweets ad product, Tweeter has introduced another type of advertising: Promoted Trending Topics, where brands pay to appear below the "trending topics" on the site. The first company to try out the concept is Disney/Pixar with the trend, not surprisingly, of Toy Story 3. It is, writes Mashable’s Pete Cashmore in a guest post at CNN, an ingenious idea: "the perfect way to generate revenue from the popular social network without infuriating users…Brands long to be a part of the conversation, and Promoted Trends create buzz around a product or service without vexing the user."

Still, the new ads do introduce a new worry for the site, despite the yellow box identifying it as an ad: namely that it may be blurring the lines between genuine conversation and advertising.

That is because the promoted trends just don’t sit at the bottom of the topic list - they rise up the list of topics just as other, real trends do, or possibly fall off and disappear from the list, based on the company’s view of how much they "resonate" with users, GiagOm says. It is fair to ask how that decision made - on the number of people who actually retweet the trending message, or based on the fact that it’s a paid ad? "Twitter is now trying to do two mutually exclusive things," GiagOm concludes. "Be a smart communications network with filters that help users discern what it’s important, and sell ads that are mixed in with those filters. It’s going to be a tough line to walk."

Also, another drawback to Promoted Topics is its cost, Cashman said: the price of the ads is said to be in the tens of thousands putting them well out of reach of small businesses.

Success?

Marketers are still getting a handle on the ROI of Twitter’s first ad endeavor. The company is expecting hundreds of advertisers to use Promoted Tweets by Q4, according to an interview COO Dick Costolo gave to Reuters.  So far, Costolo said, Promoted Tweets have been "successful beyond our wildest dreams." The first wave of companies using the program have reported excellent results. Virgin Airlines, for example announced its expansion into Canada solely via Promoted Tweets with a promotional offer - 50% off for the first 500 travelers - selling out in three hours. impressions.

There are doubts brewing in the industry, though, that such successes can replicated. Writes eConsultancy: "It's worth considering that no marketer taking a leap of faith on a new advertising platform is going to come out two months later slamming it. After all, few marketers want to look dumb and most media buyers, like most of us, prefer to remain employed. Given this, I think it's wise to take anything marketers say about a new advertising platform they're using with a grain of salt."