After years of speculation, Twitter has recently launched it own advertising platform. Promoted Tweets are display ads that show up when Twitter users search for keywords that the advertiser has bought to link to the ads. When a Twitter user searches for a keyword the promoted message shows up at the top of the results with a small message saying they are promoted posts.

The first brands to use Promoted Tweets are Best Buy, Virgin America, Starbucks and Bravo.

Twitter is charging a CPM price for the advertising with plans to adjust the model once Twitter can gauge how the ads are working.

The danger for Twitter is alienating users who don’t want to see ad messages in their tweets.

Meanwhile, other companies that have injected ad messages into users feeds using Twitter’s API, including Magpie and IZEA, may no longer be able to operate as Twitter’s COO Dick Costello has stated Promoted Tweets will be the only ads allowed to be served.