The central debate on Wall Street is starting to sound something like this: Bears say, "It's starting to look like 1999 – sell tech stocks," while bulls counter, "It's starting to look like 1999 – buy tech." This disagreement over whether to embrace or recoil from the market's resemblance to the final frenzy of the late-'90s tech-dominated bull market grows in part from certain technical extremes being reached combined with atmospheric similarities to a former moment of all-consuming attention on a tech innovation wave.