Twitter announced today that its Promoted Tweets advertising units will start rolling out at the top of users’ timelines. Until now, Promoted Tweets only appeared in Twitter searches and sidebar trends.

Now, if a user follows one of the brands or charities on Twitter participating in the program, the tweets from that company will appear at the top of the user’s timeline regardless of when it was sent out. Once seen, the tweet will scroll down the timeline like any other update and can even be dismissed entirely with a click.

Companies in at launch have been limited as Twitter tests out this new offering. Dell, HBO, Starbucks and others have already jumped on board. Charities such as The Make-a-Wish Foundation and The American Red Cross have also signed up.

If the user response is positive, expect Twitter to roll this out to all companies looking to boost their Twitter presence through paid advertisement.

[Source: Twitter, Image credit: Rosaura Ochoa]