A banner adorns the facade of the New York Stock Exchange in advance of Twiiter's initial public offering, Nov. 7, 2013, in New York. (Kathy Willens/AP Photo)

The big excitement on Wall Street has been all about Twitter.

The social media company had a very strong start but analysts warn trading may be choppy in the days ahead. Twitter's stock jumped 73% on its first day of trading on Thursday, closing at $44.90.

"I think it's clear that more investors like this IPO than we anticipated," said Doreen Mogavero, president and CEO of the investment firm Mogavero & Lee.

Twitter's hot start may prompt a wave of investor interest in new share issues, especially from Internet companies. But in the days ahead, Twitter will be under a lot of pressure to keep the enthusiasm going.

"Twitter really has to make sure they perform well," said Brian Blau, consumer research director at Gartner. "Quarter by quarter they're going to have show increases in user engagement and user growth. Twitter is going to have to show a move toward profitability and a reduction in the expenditures that they have."

There's room for caution, according to Steve Cortes, managing director at brokerage firm Lazard Capital Markets. "There are some signs that this could be a hashtag bubble."

Twitter a great company, Cortes said, but advises investors to be cautious. "Let's say your son is an excellent high school quarterback. It would be like buying a mansion for him now on the prospect that he's gonna be a first-round draft pick ," Cortes said. "That's kind of where Twitter is."

The stock market pulled back from the record high reached on Wednesday. Analysts say investors are worried that stronger-than-expected economic results could result in an early pullback by the Federal Reserve from its economic stimulus. The Dow Jones index dropped 153 points. The Nasdaq fell more than 74 - nearly 2%.

The first estimate of 3rd quarter U.S. economic growth by the Commerce Department came in at an annual rate of 2.8% - well above expectations. The market has had a terrific year, said Chris Bertelsen, chief investment officer at Global Financial Private Capital. "You blow me over with a feather if 2014 is up as much as this year."

Disney reported strong 4th-quarter profit growth, with a 12% earnings increase compared to last year. Revenue rose 7%. The strong results got a lift from Disney's parks division, which includes Disney Cruise Line. The company says higher ticket prices at Walt Disney World and Disneyland contributed to a rise in per-capita guest spending. Operating income rose 30% at Disney Consumer Products.

An eight-day trial to determine Detroit's path in bankruptcy is closing with final arguments from the city, retiree groups, unions and pension funds. Detroit filed for Chapter 9 protection in July, but a judge must determine whether the city is eligible to be in bankruptcy court. Critics say that emergency manager Kevyn Orr wanted bankruptcy for months and didn't want to try good-faith negotiations before filing. The last witness was the president of the Detroit police union. Closing arguments could last all day today.

Standard & Poor's has downgraded France's credit rating by one notch to "AA." In a statement today, S&P said it feared the French government will struggle to reduce its deficit and debt and make the necessary reforms to make its economy more competitive. The firm also said it thinks unemployment in France is likely to remain high until 2016 and that this will make reforms politically difficult. In addition, S&P said France has little room to raise taxes further to plug budget holes.

Follow ABC News Business Correspondent Richard Davies on Twitter @daviesnow.