09/14/2011 09:56 EDT | Updated 11/14/2011 05:12 EST

Twitter Starts Serving Unsolicited Ads


Twitter has begun delivering advertising "tweets" to some users, even if they don't follow the company that bought the ad.

The micro-blogging and social networking service has allowed advertisers to purchase such "promoted tweets" since 2010. It started inserting them in users' Twitter streams in July. However, up until this week, the promoted tweets would only appear for users who follow the company behind the promotion.

"Promoted tweets are entering a new phase," Twitter announced through its @twitterglobalpr account Tuesday.

The tweet linked to a Twitter help centre page on promoted tweets that explained the new phase will be "rolling out slowly this fall."

"During that time, only a limited number of Twitter users will see ads in their timeline," the site said. "And, those users will only see a promoted tweet in their timeline if an advertiser's promoted tweet is likely to be relevant to them."

It added that the platform figures out if the tweet is likely to be relevant using information such as what accounts the user follows and what they retweet.

"During this initial rollout, we will be conservative about the number of promoted tweets that people see in a single day," it said.

Users will not be able to opt out of seeing the ads. However, the ads will be marked as promoted tweets and can be "dismissed" with a single click.

"As always, we are paying close attention to how consumers interact with promoted tweets and we'll continue to make iterations and improvements as we better understand consumer reaction," Twitter said.

In addition to appearing in users' timelines, ads will continue to appear at the top of search results — the place where they first rolled out in 2010.

Twitter also announced Tuesday that it is launching a web analytics tool that will help website owners "understand how much traffic they receive from Twitter." On its Twitter Developers blog, the company said the feature will be introduced to a "small pilot group of partners" this week and will be made available to all website owners within the next few weeks.

Twitter, a privately held company launched in 2006, reported on Sept. 8 that it has 100 million active users.