Promoted Tweets, a.k.a. advertisements, will now be appearing on your Twitter stream the micro-blogging giant has announced.

The good news is that you won't be getting tweets from any old Terry Tibbs trying to sell you a used car - you'll only get notifications from organisations that you follow, and you'll also only see the Promoted Tweets once in your timeline although they will have a prominent position near or at the top of your stream.

Twitter is beginning the program with several partners signed-up including Best Western, Dell, Gatorade, Groupon, HBO, JetBlue, LivingSocial, Microsoft Xbox, Red Bull, Sephora, Starbucks, TNT and Virgin America so if you follow any of these expect to see some promotions pop up.

Charities and NGOs are also on board as well, so it's not all a corporate love-in. If you follow Make-A-Wish Foundation, Room to Read, The American Red Cross or Water.org you may also see some Promoted Tweet action.

"From the start, our philosophy around advertising has been simple: We put our users first and strive to create products that enrich the Twitter experience for every Twitter user. We’re excited about this next step and look forward to your feedback," read a post on the Twitter blog.

We can't really see that Promoted Tweets from organisations you like is much of a bother, after all you're obviously interested in that company in the first place or you wouldn't have followed them.

Promoted Tweets from non-followed sources, if that ever arrives, is a different matter entirely though....