There are many warning signs that the stock market is getting top heavy, but the Twitter IPO may not be one of them.

Twitter prices Wednesday afternoon in a week that has 16 scheduled (Initial Public Offerings) IPOs, the most in any week since 2006, according to Renaissance Capital. Last month's 30 initial offerings made it the best October since 2004, and Renaissance says 2013 is on track to be the best year since 2000.

(Read more: Twitter's three founders reunite for IPO road show pitch)

"Twitter's the most well-known of the IPOs, but the IPO calendar is more important," said Art Hogan of Lazard Capital. "We just had the best month for IPOs since 2007, and the pace continues. What that speaks to is the market can sustain the supply of stock that is coming in. Companies that have been thinking about going public have decided to because the market conditions are favorable. People look at that as a bad sign, but that's not so."

"The IPO market is a barometer of market strength, it's not the other way around," Hogan said.

Traders, of course, cannot help but compare the social networking company's debut to that of rival Facebook, whose initial offering in May, 2012, was foiled by technical problems at Nasdaq and over aggressive pricing. Facebook also came to market at a time when Europe was spooking investors.

"A lot of people are calling it a top, or a bubble, but we're still a lot lower than where we were in the late 90s," said Justin Walters, co-founder of Bespoke. "I think this is more a return to normalcy. This is a healthy IPO market. It's all based on supply and demand. I think the fact that Twitter's going on the NYSE has people more at ease."

(Read more: As Twitter IPO prices, poll says it's not worth hype)

Twitter is taking a more conservative approach than its social media rival. Facebook's offering was surrounded by hype and its stock ended up trading below its offer price for months. "The market conditions are much more conducive for this IPO for sure, but the pricing is very different too. They're not trying to get every nickel out of this that they can," said Bob Doll, chief equity strategist at Nuveen Asset Management. "The management of Twitter is very aware of that. Leave some of it. Don't take it all. It will help you in the long run."

But traders say as the company's offering range has been raised, there's less opportunity for the stock to pop on the open. Twitter's offering price is now expected between $23 and $25, and traders say it would not be a surprise to see the range raised. The average first day pop for an IPO this year is 17 percent, the highest in years, and well above last year's 14 percent and 2011's 10 percent, according to Renaissance.

Renaissance's Kathleen Smith said in a note that the market is showing some signs of froth, pricing certain sectors richly and social media is one of them.

"Some segments of the IPO market are frothy, particularly the fast expansion consumer chains, cloud computing, biotech and social networking firms. At such high valuations, as the companies report earnings, any slight disappointment will knock down prices dramatically," she noted.

(Read more: IPO Tsunami looms, may even drown out Twitter)

Twitter may not be commanding the premium Facebook did but it seems to have more fans among the Wall Street crowd that use it for news, market information and gossip. "The investor class is probably warmer to Twitter than they were to Facebook, and people were crazy over Facebook," Walters said. "The fact that it's not nearly as big an offering as Facebook is good."

"Facebook is neat and Twitter is essential," said Hogan. "People use it as a news service now. That's how they stay current. I don't stay current following which restaurant my cousin likes. I care what's going on in the news."

So far this year, there have been 182 IPOs, compared with128 for all of last year and 125 the year before, according to Renaissance.

"We expect to finish the year with over 225 IPOs raising $50 billion in proceeds and that will make 2013 the most robust IPO market since 2000. At the high end of the proposed $23-$25 range, Twitter would raise $1.75 billion, making it the third largest IPO of the year, and its market capitalization would be $17 billion making it the most highly valued IPO since Facebook," according to Smith.

(Read more: On eve of expected IPO, Twitter has new top bird)

So far this year, IPOS have had an average return of 33 percent, while its own Renaissance Capital Global IPO Fund is up 42 percent.

"Twitter may be the top of the IPO market for the year, but it's that time of year," said one trader, adding stock offerings typically slowdown in December but they are likely to pick up again in the first quarter.

—By CNBC's Patti Domm. Follow here on Twitter @pattidomm.