Twitter Inc posted the slowest revenue growth since it went public four years ago, sending shares down more than 10 percent on Thursday on fears that rivals Snapchat and Facebook Inc were winning the war for advertising. Revenue from advertising fell from a year ago and a 4.0 percent year-on-year rise in users to 319 million fell short of Wall Street forecasts as well. The election of prolific tweeter Donald Trump as U.S. president failed to produce a "Trump Bump" in Twitter's results, and Twitter declined to give guidance on future revenue with Chief Executive Jack Dorsey asking for patience.