By Hollywood standards, it was low on glitz. But the all-text plug for Toy Story 3 that appeared on Twitter yesterday is already being talked about around the world. Disney-Pixar is hailed as the first advertiser to take part in Twitter’s latest ad platform: sponsoring the trending topic. So far, the judiciously placed Tweets appear to be doing the job of buzz-building. But the verdict is still out on this form of minimalist advertising. Here, we take a look at which companies, brands and products would be wise to sponsor trending tweets, and which ought to stay well away.

One thing is for sure, buying a Promoted Trend gets the word out there fast. This graph represents the numbers of Tweets mentioning “Toy Story 3″ in the past two weeks. Notice the huge jump as of yesterday, timed of course to the box office opening this weekend in 22 markets, including the U.S.

With that much built-up momentum, it would make sense for Disney-Pixar to put its stamp on the conversation and get is message out there above the rest. But is investing in a Promoted Trend a good idea for every brand? Probably not. Here are a few examples to illustrate when Promoted Tweets could probably work to benefit the brand, and then again when they probably wouldn’t.

First, when it makes sense:

• C0-opt the Zeitgeist — For this category, think big movie premiers like Toy Story 3 and cult entertainment like the finale of “Lost,” pop culture moments that everyone will be talking Tweeting about. A Promoted Tweet in this case, as seen with Toy Story 3 above, is a wise way to spike the conversation arc even further, and when it is most convenient for the company. This feeds off the concept of viral marketing tactics to amplify the impact of something with blatant grassroots possibilities.
• Crowd-Source This! — In April, Dunkin’ Donuts launched a major crowd-sourcing campaign, asking the general public to channel their inner Homer Simpson to devise the next great donut flavor. They had thousands of participants and countless blog posts comparing and discussing the various recipes, and it seemed like the more attention and conversation surrounding the contest the better. Customers could engage other customers to discuss their favorite donut maker, precisely what DnD had in mind. After all, this was totally benign territory: the only negative discussion regarded bad customer entries. The company could do no wrong in this context. Here, a Promoted Tweet could generate even greater participation in a crowd-sourcing contest. Who knows? It may have even inspired someone to top this year’s winner: a banana-filled-chocolate-icing-topped-with-peanut-butter-shavings creation.
• The virtuous do-gooder campaigns
  The first thing that comes to mind here is the Pepsi Refresh Project, which brought Pepsi fans together on social networks to discuss and vote for civic-minded projects submitted by fellow Pepsi fans. The community vote winners were then funded by Pepsi to carry out their project idea, thereby increasing brand popularity for Pepsi and simultaneously fixing up the old park down the street. Who could possibly have anything bad to say about this? Ogres, maybe. Here’s an initiative of the people for the people. The more people that participate, the logic goes, the more clever the ideas and the more positive the word-of-mouth buzz.

And when you might not want to buy that Tweet:

• F#%@ing With The Formula — Ever since Coca-Cola changed the traditional formula to the New Coke way back in 1985 and sales tanked, marketers have had the message ingrained into their heads: don’t mess with success. And yet they still do. See: Pampers Dry Max. Promoted Tweets may be new ground for marketers, but one thing we know: it’s probably not a wise ad buy for that unproven recipe amongst a still divided public.
• Anal geek warning – What happens when a company releases a brand new product never before seen by humanity? We are thinking more along the lines of, say, the iPad. It is extremely technical, so there is always room for computer glitches and, lets accept it, tech geeks are never fully satisfied with a newly released gadget. Renting out a Promoted Tweet for such a launch is fraught with risk. Gadget geeks are prone to tweet their frustrations, and amplify any bad reviews, even those found in even obscure trade publications. Spending the marketing outlay on a promoted Tweet here could just fuel the angry fire.