Twitter still trying to monetize: in-stream tweets?

One of the most popular social sites can't seem to get revenue right

Tweets from my friends, tweets from my favorite musicians, tweets from the New York Times, tweets from NASA and... tweets from random advertisers?

Twitter is reportedly toying with the idea of placing advertisement directly in users’ streams, according to sources with knowledge of the plans.

While marketing on Facebook has taken off in large part due to brands’ and businesses’ ability to curate Pages with all the content they want, Twitter has not yet offered anything comparable. And yet, instead of giving advertisers a way of breaking free of the 140-character limit, today’s report suggests that Twitter may go a different route.

It’s a delicate line to walk, however, because obtrusive or irrelevant tweets could be seen by users as ruining the Twitter experience. We’ve seen this before, in a way, with the messy implementation of the QuickBar on Twitter for iPhone.

The Twitter moneymaking problem has been an important issue since last year, when “Promoted Products” launched as the company’s first foray into a paid advertising. The suite includes Promoted Tweets, paid tweets that show up in targeted search results; Promoted Trends, trends that show up alongside other trending topics of the day; and Promoted Accounts; accounts shown alongside other accounts that users are suggested to follow.

In spite of nothing but positive words about the Promoted Products from Twitter’s top-level executives, it’s well-established that the site, second only to Facebook in social networking clout, should be bringing in more revenue. While eMarketer estimated at the start of the year that Twitter could bring in $150 million this year, that number could be a lot higher.

In 2011, Twitter must mature its revenue model, and it knows it. We know this because the company just a couple weeks ago acquired Internet advertising startup AdGrok for an undisclosed amount. And that was just two months after AdGrok raised angel funding.

To learn more about how Twitter can better get revenue from marketers, be sure to watch this interview with Buddy Media CEO and founder Mike Lazerow.