(FILES)The Twitter logo is displayed at the entrance of Twitter headquarters in San Francisco on March 11, 2011 in California. The wildly popular Twitter website went offline briefly for many users June 21, 2012, prompting a flurry of complaints on rival sites. « Users may be experiencing issues accessing Twitter, » a company statement said. « Our engineers are currently working to resolve the issue. » Around an hour later, Twitter said: « The issue has been resolved and all services are currently operational. » AFP Photo / Kimihiro HOSHINO /FILES