MySpace is the largest social networking site, but the attorneys general called on others in the industry to adopt these principles as well, Allen said.
Others pointed out potential problems.
Barry Wellman, a University of Toronto sociologist who studies online gatherings, said MySpace still might have difficulty monitoring older users who create underage profiles.
"It's obviously easy to lie in that situation," Wellman said.
Wellman and Avi E. Rubin, a professor at the Johns Hopkins University, said that the agreement that allows parents to submit children's e-mail addresses to MySpace would be useless if kids have multiple addresses.
"Many teens would see that as a challenge to get around rather than a prohibition," Wellman said.
Rubin said, "A teenager can create his own e-mail address that parents don't know about in about two minutes."
And such a database of blocked e-mails would be very valuable information that would be targeted by hackers, Rubin said.
"That would be a database you would know are children," agreed Guilherme Roschke, of the Electronic Privacy Information Center. He said the plan overall contained some good changes, including limiting the ability to use search engines to find private profiles.
The agreement states that MySpace will prohibit tobacco or alcohol advertising, but using algorithms to identify underage users could let someone direct advertising to children, Roschke said.
States sought changes in response to concerns about sexual predators, and the report follows two years of discussions between MySpace and the attorneys general, according to Gansler's office.
Last year, Gansler, a former state's attorney, introduced a statewide program intended to educate children about potential online dangers, including sexual predators and identity theft.
Yesterday's agreement was announced in New York City by attorneys general from New Jersey, North Carolina, Connecticut, Pennsylvania, Ohio and New York.
Investigators have increasingly examined MySpace, Facebook and similar social networking sites that allow people to post information and images on the Web and invite contacts from others.
Last year, New York investigators said they set up Facebook profiles as 12- to 14-year olds and were quickly contacted by other users looking for sex.
The multistate investigation of the sites - announced last year - was aimed at putting together measures to protect minors and remove pornographic material, but lawsuits were possible, officials said.
liz.kay@baltsun.com
Sun reporter Brent Jones and the Associated Press contributed to this article.
