Live from the NYSE floor on Twitter's first day of trading NEW YORK -- Floor traders are filtering into the New York Stock Exchange an hour before Twitter makes its debut as a public company. They sipped coffee, put on their ties and characteristic blue coats as reporters and photographers filed in. Duncan Niederauer, chief executive of the exchange operator NYSE Euronext, said the firm has conducted several weekend tests with Wall Street firms. LIVESTREAM: Watch Twitter executives ring the NYSE opening bell "We've had no trouble getting people engaged in the weekend tests," he said. And you could say those were unnecessary precautions -- we've done a lot of IPOs this year -- but I think it's better to leave no stone unturned on this one. In the end, the extra preparation won't matter if Twitter's IPO goes smoothly. "Our job is to not set the price," Niederauer told the Los Angeles Times as he stood near the Barclays post on the NYSE trading floor. Our job is to make sure that the market dynamic works, everyone can get their orders in, and we open the thing smoothly and trade from there. Niederauer and Larry Leibowitz, chief operating officer, were off to have breakfast with the Twitter team about an hour before the opening bell. Traders would not be live-tweeting the IPO. Not only are there restrictions on using mobile devices and electronic communications because of compliance issues, some may be unfamiliar with the microblogging site. "I don't know how that works," one trader joked when asked if he would be tweeting. My kids do.