But this time, as millions of packets streaked through the network, AOL's computers went on red alert, mistakenly identifying the mailings as a wave of unsolicited bulk email, or "spam." Topica representatives said that as many as one in five of the company's messages to AOL addresses were bounced.
As the courts and Congress lag in placing limits on spam--one of the Internet's most reviled by-products--companies that offer email services, including AOL, are moving ahead with technological fixes that may go too far in dealing with the nuisance of bulk email.
Many of AOL's subscribers have applauded the company for installing email filters that can drastically cut down on the junk email that bombards their in-boxes. But some companies, such as Topica, say that many legitimate messages also are being shut out.
"It appears that recently, AOL made their filter more narrow and more intense, and that triggered this blockage," said Ariel Poler, Topica chief executive.
AOL spokesman Rich D'Amato confirmed that the company's anti-spam efforts unintentionally blocked Topica's email.
"As part of our efforts to protect AOL members from junk emails, we took some anti-spam action that inadvertently resulted in some legitimate Topica email not being delivered to AOL addresses," D'Amato said.
D'Amato said AOL has "remedied the issue," and that the flow of Topica email has continued at a regular pace.
Topica's experience underscores the challenge spam poses to Internet service providers, which are being recruited as gatekeepers in the battle against bulk email.
AOL has taken a range of actions against spammers, from blocking their email to taking alleged violators to court. More recently, it installed filters to shunt unwanted mail from recipients before it reached their in-boxes.
D'Amato refused to discuss specifics of AOL's technology, saying that spammers could use that information to work around the company's filters. But he said AOL commonly tries to identify email that meets "certain characteristics that we use to identify what has the potential to be junk email."
Companies that send email lists to AOL members said they usually have to inform AOL not to block their mailings. Otherwise, many of these bulk emails could be identified as unsolicited mail by AOL and blocked from entry.
"They have to figure out which (Internet Protocol) addresses can be accepted," a representative from Evite.com, a Web- and email-based event planner, said about AOL. "Otherwise, the spam filters may get you."
Web email giants such as Yahoo and Microsoft's Hotmail also have taken steps to curb spam. Both companies have instituted ways to keep junk mail out of in-boxes, but with mixed results.
Last November, Hotmail came under fire after it subscribed to the Mail Abuse Prevention System's (MAPS) Realtime Blackhole List (RBL), which blocks email coming from servers known to be conduits for spam. People criticized the move because it did little to slow the tide of spam into their in-boxes but potentially disrupted legitimate email.
Spam-watchers have long cited the obstruction of legitimate email as a negative side-effect of a reliance on email filtering technology.
John Mozena, co-founder of anti-spam advocacy group the Coalition Against Unsolicited Commercial Email (CAUCE), is critical of companies that depend on technology to protect consumers against spam. Instead, Mozena says legislation is required to stop spam at its source: the people who create it.
"The legislature and the courts are the right places to address this issue. It's not a technological problem; it's a social and legal problem," Mozena said.
"(ISPs) shouldn't have to write filters," he added. "They shouldn't have to spend time and money to protect their users and their networks from unscrupulous advertisers."
But the spam question is a complex issue from the legislative side. In March, a judge ruled that an anti-spam effort by Washington state violated the U.S. Constitution. King County Superior Court Judge Palmer Robinson dismissed a lawsuit brought by state Attorney General Christine O. Gregoire against Jason Heckel of Salem, Ore., claiming the law was "unduly restrictive and burdensome," hurting legitimate businesses more than it helps consumers. The government has appealed.
In the meantime, the U.S. House of Representatives is considering a raft of legislation to rein in spam. The leading bill, H.R. 3113, would create a nationwide list of people who do not want to receive junk email. Called the Unsolicited Electronic Mail Act of 1999, and written by Rep. Heather Wilson, R-N.M., the legislation would have the Federal Communications Commission (FCC) oversee and maintain the list. The FCC would penalize those who sent spam messages to members of the list.
News.com's Paul Festa and the Associated Press contributed to this report.