• by Augie Ray , November 2, 2010

Twitter watchers have long waited (and some feared) this moment: Ads are coming to your Twitter timeline. Twitterers thus far have supported and shown little concern over Twitter's Promoted Tweets program, as long as those paid tweets were easily differentiated from unpaid tweets and stayed within search results or at the top of the Trends list. But now Twitter is taking the next step that many expected and inserting promoted tweets into users' Twitter streams, and that means co-mingling authentic, unpaid tweets with paid, advertising tweets.

This is the riskiest move Twitter has ever made. There is a big difference between displaying paid tweets at the top of search results and inserting them into the timeline -- just ask search engines, which for a while in the early days of the Web struggled with their own monetization models. Search engines experimented with co-mingling paid-search ads with organic search results, but the backlash from consumer advocates and users was sufficient to force a different model. Today, paid-search ads are not just differentiated with words, colors and fonts, but are substantially and consistently separated from organic results into special portions of the screen.

In some respects, Twitter is now experimenting with the old, failed model abandoned by search engines, but of course there are differences between search results and a stream of tweets. The former is a response to user input that is expected to be the best, objective match for users' stated needs; the latter is a dynamic flow of user-generated content.

Search results are more like a digital encyclopedia (an impartial reference book) while tweets are akin to radio (a stream of news, opinion and entertainment), and this distinction may be enough to bring Twitter advertising success where search engines failed. But if users feel Twitter presents too many paid tweets or these tweets are insufficiently differentiated from organic tweets, it could cause complaints, diminish usage and slow Twitter as it closes in on the 200-million-user mark later this year.

The primary risk to Twitter introducing Promoted Tweets in the timeline is not a catastrophic migration of users but a slow, grinding and difficult-to-reverse loss of confidence, trust and usage. Although this move is fraught with peril, one cannot be familiar with Twitter's history and expect it to stumble as it deploys Promoted Tweets into users' timelines. There are four reasons to bet Twitter will avoid problems:

· Twitter moves cautiously: As it has with every step in its Promoted Tweets journey, Twitter is moving slowly. Promoted tweets will only appear in the timeline of Hootsuite users at this time, and all parties will be monitoring reaction.

· Twitter recognizes that it doesn't know it all: While some have found Twitter's progress on monetization maddeningly slow, I've respected the spirit of experimentation they've brought to their Promoted Tweets program. As noted in Matt Graves' blog post on the Twitter blog: "We're carefully looking at how Twitter users react to and engage with Promoted Tweets in the timeline... We will expand the rollout only when we feel we're delivering a high-quality user experience."

· Twitter cares about relevance: Twitter is in search of a bold, new ad model based on relevance. This isn't just the quest to present the right ad at the right time based on your surfing or searching habits, but is instead a real-time monitor of consumer interest in and reaction to ads. This democratization of advertising will mean that ads that meet with user acceptance live on while those that fail disappear quickly and painlessly.

· Twitter is not afraid to pull the plug: Not only does Twitter not proceed unless it is confident that users will accept a program, it also isn't afraid to pull the plug. Within months of the launch of Twitter's Early Bird program (sort of like a Groupon for tweets), the company reversed course. Because the stakes are so high, I don't expect Twitter will give up on Promoted Tweets in the timeline, but the company's willingness to alter plans based on user reaction remains encouraging.

Consumers are rarely eager to see more ads, but I believe Twitter is poised to do it right. So what do you think -- will Twitter succeed by furnishing relevant and welcomed advertising, or are they at risk of killing the goose that utters the golden tweets?