[ by Melanie Gretchen ] Twitter is about to sell its users' data to marketers, including archived tweets and basic information, like geographic location.  The online social networking service has granted two companies Boulder, Colorado-based Gnip Inc and DataSift Inc, based in the U.K. and San Francisco, to release information to clients who will pay for the privilege of mining the data. Sale Details. Twitter is keeping mum on the sale, instead deferring questions to DataSift.  DataSift will release Twitter data in packages that will cover the last 2 years of activity for its customers to mine, while Gnip will have access to the last 30 days. DataSift. As its name suggests, this platform will sell tweets on specific topics and even isolate those views based on geography.  Currently, upward of 700 companies are on a waiting list to see its results,  according to DataSift CEO Rob Bailey in an interview with Reuters. When the site made all of its tweets available to the U.S. Library of Congress in 2010, stated restrictions by Congress included a 6-month delay and a prohibition against using the information for commercial purposes. Based in San Francisco, he said the effect is something like holding a huge number of sporadic focus groups on brands or products. For example, Coca-Cola could look at what people in Massachusetts are saying about its Coke Zero, or Starbucks Corp could find out what people in Florida are saying about caramel lattes.  Companies can also look at how they have responded to consumer complaints. Gnip. This company offers the short-term data package.  It said the information collected - involving real-time viewing - can also be used during natural disasters to help rescuers, to monitor illnesses such as a flu outbreak and to analyze stock market sentiment. Reception. "As we see Twitter grow and social media evolve, this will become a bigger and bigger issue," said Graham Cluley, senior technology consultant for British-based Internet security company Sophos Ltd. "Online companies know which websites we click on, which adverts catch our eye, and what we buy ... increasingly, they're also learning what we're thinking.  And that's quite a spooky thought." Mr. Bailey said no private conversations or deleted tweets can be accessed.  Companies want aggregated data, not to try to figure out who said what to whom.  "The only information that we make available is what's public," he said. "We do not sell data for targeted advertising.  I don't even know how that would work." A digital analytics expert said the biggest impact will be for marketers.  "The only privacy risk is marketers being able to do more with the data, faster," said Thomas Bosilevac, director of analytics for the digital marketing company Digitaria. Backlash. Not everyone is embracing Twitter's potential.  "It's frustrating, and telling, that now marketers have greater access to my old tweets than I do," said Rebecca Jeschke, digital rights analyst and spokeswoman for the non-profit Electronic Frontier Foundation.  "However, this is perfectly legal, if creepy.  If you publish your tweets publicly, that allows all sorts of folks to do all sorts of things with them." Damage Prevention. What users can do is go back and delete old tweets.  DataSift is required to regularly update its files to remove comments that have since been deleted.  Unlike when you're looking for someone else's tweets, users can always see their own simply by clicking on the word "tweets." For further details, go to [Reuters, 3/1/12].