It wasn’t too long ago that Twitter got involved in the advertising business by announcing promoted tweets and plugging them into your stream whether you followed the source account of not. Now, in an effort to explain their advertising horizons, Twitter is announcing a new variety of promoted tweets: Political ads.

You’ll be able to tell what tweets are political promotions based on the little arrow in the bottom right corner. If it is purple, it’s political. Orange is commercial. A number of campaigns have already hopped on this opportunity including, the Democratic Senatorial Campaign Committee and Mitt Romney. The Washington Post reports that the promoted tweets will come as search results, but also in the timeline of users who follow a political campaign. Let’s hope Twitter is smart enough to narrow down the appropriate party to promote to a given account.

A few months ago, we reported that Twitter ads were taking the next step and putting Promoted Tweets, otherwise known as ads, in users’ streams. The upside to this was that if a user wasn’t following the Twitter account from where the Promoted Tweets originated, said user would not see the Promoted Tweets. However, that didn’t seem to last very long, as Twitter CEO Dick Costolo said that Promoted Tweets are going to take another next step, and will appear to everyone, whether or not a user is following the account from which the promoted tweet originated.

Costolo said:

“We’re expanding Promoted Tweets.

You’ll start seeing them from companies you don’t follow. We’ve been super cautious about that, we didn’t want to sacrifice user experience.”

And yet, here we are. The Promoted Tweets, however, won’t just be a random sampling of ads from Twitter.

You may have noticed that Facebook recently introduced a feature called the ticker. You may have wondered, considering it’s often sitting right next to your newsfeed, exactly what it is for. Well, we have a pretty good guess, it’s for Facebook to experiment with sneaking sponsored content into your update stream with the hopes that you’ll click on it before noticing it’s an ad.

Now if you were to take a good look at the ticker, you could see that it does have a different purpose than the newsfeed. While the newsfeed purports to provide news, the ticker provides news that is too mundane for your newsfeed. Remember all those FarmVille stories you blocked? The ones about how Steve now owns 37 cows and employs 4 migrant workers? Those are now ticker material and it seems that Facebook is hoping the banality of those updates will dull your senses to the exceedingly similar ads that will also appear there.

Twitter‘s relationship with advertising has been a bit of a saga, but now it seems that “promoted tweets” are finally going to be put into action. In short, promoted tweets, or what you might call advertisements, will now start showing up in your main tweetstream, if — and only if — you follow a particular brand. For instance, you won’t have to deal with promoted Coke tweets if you are a devout Pepsi fan, as doubtless you are.

For the moment, this new promoted tweet thing will only pertain to certain beta-testing companies like Starbucks, Groupon, Dell and Gatorade. (Full list here.) On the upswing, it appears that promoted tweets will also be available to charities as The Red Cross and the Make-a-Wish Foundation are included in the beta organizations.

After purchasing the second ever promoted tweet, Coke saw astounding results. In just the first 24 hours after the promoted tweet went online, the ad saw over 85 million impressions. Not only that, but the ad saw a 6% engagement rate, as opposed to the usual .02% estimated with other web-based advertising. That’s over 5.1 million people who interacted with that ad in just a 24-hour span.

This could be just what Twitter needs for advertisers to see that it’s a useful medium for getting the word out; Twitter just has to be cautious not to let it get out of hand down the road, as too many promoted tweets could spoil the microblog for everyone.

It’s no great secret that even after building one of the hottest social networks online, Twitter still hasn’t quite figured out how to monetize what they’ve got. They had a big break in getting $25 million from Microsoft and Google for the privilege of indexing their Tweets, but that’s hardly a sustainable source of revenue. But their latest strategem, as reported by Peter Kafka, doesn’t quite sound like a winner: Charging advertisers “tens of thousands of dollars” to buy an exclusive slot on the Trending Topics list.

Twitter developers beware. TweetUp, which has been hailed as the “Adsense for Twitter,” was announced today at TechCrunch‘s Disrupt event. TweetUp is an ad platform that would give its advertisers access to analytics, an algorithm designed to rank keyword searches in a promotions-friendly manner, and, most tantalizing, a 50/50 revenue split. Basically, individuals and businesses could pay to promote their tweets to the top of any search with a relevant keyword in it, chronological order be damned.

But on the same day as the TweetUp announcement came today’s post on the Twitter blog, wherein Dick Costolo, Twitter COO, plays the part of the valiant knight defending Twitter’s integrity against those pesky third parties. In said post, he writes, “aside from Promoted Tweets, we will not allow any third party to inject paid tweets into a timeline on any service that leverages the Twitter API.”

This all comes shortly after the announcement of Promoted Tweets – tweets paid for by advertisers including Best Buy, Red Bull, and Starbucks that show up at the top of searches. Everyone wants to make money off Twitter. Even Twitter! But now, apparently, only Twitter actually can.

Twitter is about to get serious about making money. They’ve just rolled out their long-awaited advertising program, which they call “Promoted Tweets,” which consists, in a nutshell, of sponsored ads popping up at the top of Twitter search result pages. So far, so good, and pretty similar to what Google does.

Here’s the thing: In the Promoted Tweets FAQ, Biz Stone refers to this strategy as just “the first phase” of the platform. He writes that the next phase hasn’t yet been decided, but the FAQ and an interview with the New York Times both give pretty good hints of what it could include: Advertisements that follow you into your personal timeline.