A NYT article, published over the week-end, sparked a heated debate over the legitimacy and value of an in-stream advertising model on Twitter.

-This idea has no official blessing from Twitter, yet.

-Back in September, the start-up changed its TOS to include the option of integrating advertising, in its service and search. And that time is approaching.

Open questions on the in-stream advertising models, and advertising on Twitter:

• Ambiguity- Can a 2chars hashtag (#ad) disambiguate an advertisement  inside a stream?
• Control – What prevents me or a spammer from exploiting this system and deceiving my followers? Anyone could post a tweet promoting a new Starbucks Coffee, and instead send traffic to a make-money-from-the-internet landing page or to this blog.
• “Advertorialization of Content”- How will the sponsorship affect the quality of the content produced? E.g. if a user is paid to place a Sony ad in her stream, will she still tweet or link to content that is not Sony-friendly?  And viceversa, will she start bragging about Sony to make her ads look more legitimate? Or to attract new advertisers?
• One platform- What’s in for Twitter in this model? Should its own future advertising platform be the only one allowed and sub-licensed to third parties? Will this model be open for third parties like an Adsense?
• Who is paid for what – As with the Murdoch-Google case, are we taking it backwards when we sustain that content producers should be rewarded on Twitter? Aren’t they the one who are benefiting from all the attention and traffic that they receive from Twitter, and for free?
• One-size-fits-all- Will the advertising based model come with a premium service that is advertising free?  There is a target of early adopters and users repellant to advertising, who would pay for the conversation to be unadorned and uncluttered. ( Except that without the ads, some conversation might sound a little strange).
• CPM, Metrics and Retweets- What are the new metrics in this model?   Ad.ly and Izea have CPM offers, where the CPM value is inferred from the influence of the Twitter user (followers, lists and their members and followers, retweets, engagement through @replies, etc). A caveat though: unlike traditional impression-based models, tweets tend to have a very short life span.  But it is also true that when the attention is captured, the ad could spark a word of mouth effects inside and outside Twitter, that is much more valuable than a pure CPM. Are there measurement tools to allow for this post-click analysis of a campaign ROI? Will users be able/prompted to retweet ads?
• Search vs Stream: with search you could reach way over the number of followers of a single Twitter user, and users who are interested, when they are interested and guarantee relevancy of the ad to the published content (the tweet). With in-stream ads there is the brand association factor, but it gets diluted by a smaller reach and the randomness of when it gets shown to the users.

Geo-location APIs will help close the sales loop for businesses with a brick and mortar presence, and make local advertising a very effective component of whatever advertising platform Twitter will come up with. That’s how far my certainties go!