In an effort to beef up its advertising offerings, Twitter has today begun to place Promoted Tweets at the top or near the top of your timeline. These Promoted Tweets will come from organizations that you already follow, ostensibly making it easier to see Tweets that these brands purchase.

Twitter says that when visitors go to the site they “expect to be among the first to get a special announcement, access to exclusive content or a great offer.”

To this end, the ‘most important’ Tweets from the companies and organizations that you follow will start surfacing at the top of your timeline, rather than in a specific time slot. The Promoted Tweets will only appear in your timeline once and can be dismissed. Once they’ve appeared, they will scroll down through the timeline like a regular Tweet.

Twitter already has deals in place to begin delivering tweets to users timelines:

We’ll be rolling out and testing this new offering over the next several weeks with a select group of partners, including Best WesternDellGatoradeGrouponHBO,JetBlueLivingSocialMicrosoft XboxRed BullSephoraStarbucksSummit Entertainment’s “50/50”TNT and Virgin America among others — with more to come soon. During this phase, you may also see Promoted Tweets in your timeline from non-profit organizations you follow, including charity: waterMake-A-Wish FoundationRoom to ReadThe American Red Cross and Water.org.

The Tweets will look like any other from a brand that you follow, but will feature the ‘Promoted’ tag and image just below the message.

promoted tweets jetblue 520x261 Twitter begins placing Promoted Tweets at the top of your timeline

For now it appears that you will only see these promoted tweets if you’re on Twitter.com. You will not see them in third or first-party Twitter clients like Twitter for Mac, Tweetbot or Tweetdeck. You will also only see the ads if you follow the brand that has purchased a promoted tweet.

This is obviously a nice improvement for advertisers on Twitter as it greatly increases the chances that a user is going to see a Promoted Tweet if it’s surfaced. If a user follows a couple hundred people, they’re likely to miss a single Tweet unless they’re checking the service constantly. This way the ad can be delivered when the user is actually on the service.

This also marks the first time that Twitter is injecting Promoted Tweets directly into the timeline on Twitter.com, although they have explored this possibility in the past with partners like Hootsuite.

The Promoted Tweets ad platform was launched in April of last year as a way for advertisers to reach Twitter users directly in their streams. In July, Twitter CEO Dick Costolo said that over 80% of advertisers choose to renew their campaigns with the company. Last year, in a bid to funnel any advertising efforts through the company itself, Twitter placed a ban on other advertising firms injecting Tweets into users’s streams.