Google official Norvig said the company hasn't ruled out some kind of registration program in the future, but is reluctant to make such a move because it would slow the user down.
Meanwhile, other companies are catching up in the race for the best search technology.
"Everybody's really, really close," Search Engine Watch's Sullivan said, citing blind search-quality tests. "Google is still perceived to be the leader. But their competition can be as good or better than them on many queries."
Norvig said Google continues to invest heavily in improving its search technology, with the goal of crafting a more intuitive process. He cited recent additions to the Google arsenal -- such as product-oriented Froogle and a new service that allows users to track packages or check a flight's status -- as evidence that the company is far from standing still as the competition in search intensifies.
Google has also shown an interest in expanding outside the search arena -- it purchased the Web log site Blogger in early 2003 -- and $4 billion from an IPO could come in handy for future acquisitions.
"Their goals range far beyond what people are experiencing from them and what people are anticipating from them," said Scott Kessler, an equity analyst at Standard & Poor's who specializes in the Internet.
The idea that Google might change once it goes public is unsettling to some.
"All I hope is that Google stays the Google that it is no matter what happens," one fan of the company wrote in a discussion on Google IPO Central. "Don't sell out Google."
The same person also posted a question: "Anyone know of a way I can get in on the deal?"
It's that kind of interest, multiplied across the millions who use the company's services and now want to own a piece of it, that worries Jeremy C. Wright, a self-described "Business and Tech type person" who asserts on his blog that the Google IPO "is evil."
The hype surrounding the offering, he writes, is "creating a bubble-type mentality" that can end only one way -- with a bust.
He compares the Google IPO to another famous IPO, the Netscape offering in 1995 that is credited with helping set off the first round of Internet mania.
"Hopefully Google fares better than Netscape did," he writes.
Most Silicon Valley insiders think it will, but no one can know for sure.
"What they've accomplished in five years is nothing short of remarkable," said Think Equity's Moe. "The question is whether they have what it takes to create the next act."