December 1999:"Internet mania paid off big time for investors in 1999, and incredibly, the dot.coms have more room to run in 2000. Despite a prolonged midyear sell-off that ran from April to August, Internet stocks are up an incredible 154% this year through Dec. 10, as measured by the Dow Jones Internet Composite Index of 40 stocks. Investment pros doubt that Net stocks can repeat this kind of performance next year. Still, they see huge growth ahead for the Internet and believe that Net stocks will continue their drive north."
The dot com stocks peaked in March 2000 and then plunged for the next 2+ years. The Nasdaq Composite lost over 70% of its value between March 2000 and Feb 2003.