Twitter has finally rolled out an advertising service this week. Lending its idea from Google’s advertising model, ‘Promoted Tweets’ will initially show ads only on top of some of the site’s search results pages.

The ads are reportedly later to be shown on Twitter’s home page, tailored by the user’s interests.

The popular microblogging site has been known for its reluctance to turn to traditional advertising into a source of funding. Questions about the site’s financial sustainability have been asked as the service is operating on a free-of-charge basis.

Twitter looks to be continuing its huge success with a reported 22.3 million users this March. Together with users who access the site thorough third-party systems, the total number is estimated to be around 45 million.

According to the site, a number of big names have already signed up to use Promoted Tweets, including the likes of Starbucks, Sony Pictures, Red Bull and Virgin America.

Sources: The Guardian, BBC