Twitter confirms that it does not own user Tweets

There is a section of Users (using various internet services such as Facebook, Email services, Twitter, etc) that are very sensitive to any thought that companies might want to be claiming copyright on the content that users generate. So, for example, when Google first announced that Gmail would have advertisements running next to the email, and these advertisements would be based on the content of the email, there was some controversy about how Google would be looking at the content of user's emails to generate these ads (and it slowly died away after Google talked about a computer algorithm to derive the context-aware advertisements).
Facebook faced a problem in February 2009, when its Terms of Use scared people into thinking that the Facebook is claiming copyright over the content uploaded by users; that controversy became very large very quickly, and needed changes and announcements by Facebook management to mollify and dampen the controversy. Twitter was in danger of landing in a similar public relations problem, but they seem to have taken quick action (link to article):

Twitter co-founder Biz Stone on Thursday said that the popular online messaging site had updated its Terms of Service to clarify what users can expect from the service, though the announcement appears to be more about reassuring users than delineating substantive rights. "The revisions [of Twitter's Terms of Service] more appropriately reflect the nature of Twitter and convey key issues such as ownership," said Stone in a blog post. "For example, your tweets belong to you, not to Twitter."
"The vast majority of tweets are likely to be too short and lacking in creativity to qualify for copyright," said Fred von Lohmann, senior staff attorney for the Electronic Frontier Foundation, in an e-mail. "So they are not 'owned' by anyone, much like your idle chatter while walking down the street isn't 'owned' by anyone."