Twitter chief executive Dick Costolo has said the company will continue to defend the privacy of its users in the face of legal challenges by authorities that want to gain access to deleted content.
Speaking at the Online News Association's annual conference in San Francisco on Friday, Costolo said: "We strongly believe it is important for us to defend our users' right to protest the forced publication of their private information."
The news comes after Twitter lost its fight to withhold public tweets written by an Occupy Wall Street protester that had later been deleted.
The micro-blogging site was served with a subpoena on 26 January asking it for the tweets and account information of Malcolm Harris, who had been charged with disorderly conduct for allegedly marching on the Brooklyn Bridge last October in defiance of police orders.
Twitter told Harris of the subpoena on 30 January and Harris filed a motion to quash it, but a judge denied the motion on 20 April, ruling that the defendant had no "proprietary interest" in the user information on his Twitter account.
"If you post a tweet, just like if you scream it out the window, there is no reasonable expectation of privacy," wrote New York Criminal Court Judge Matthew A. Sciarrino Jr. in his ruling. "There is no proprietary interest in your tweets, which you have now gifted to the world."
Costolo said Twitter was disappointed that it had been forced to hand over the information, but said that the company had been put "between a rock and a hard place". The information will remain sealed until an appeal is heard.
Costolo also used his speech to defend Twitter's recent API changes, which limit the number of user tokens Twitter grants to third-party applications. This means that developers building new applications that expect to need more than 100,000 tokens will have to ask for Twitter's approval.
The decision came after the company realised it had invested significant resources in its service, but other companies were making money off of it without adding "accretive value," Costolo said.
Twitter is now working on a free tool that will allow users to curate and publish selections of tweets to accompany breaking news events. It also plans to allow users to download their entire Twitter history, and view interactive tweet boxes that host additional content such as sports results.
"We want to migrate to a world in which the 140 characters can serve as a caption for additional functionality," Costolo said.