On Wednesday, Microsoft and Yahoo announced that they would. By the middle of next year, users of both are expected to be able to exchange instant messages, see if their contacts are online, share emoticons, add friends from either service and make PC-to-PC voice calls.
But the partnership has a flipside, an instant-messaging security expert said. "As Microsoft, Yahoo and others connect their global IM networks, IM worms will spread faster and attack a larger population of end-users," said Jon Sakoda, chief technology officer at messaging security company IMlogic.
Instant-messaging service users are being hit withthan ever before. The number of threats detected for IM and peer-to-peer networks rose 3,295 percent in the third quarter of 2005, compared with last year, according to a recent IMlogic report. The company sells products to help businesses protect themselves against IM-borne pests, in competition with companies such as Akonix Systems.
"A worm could proliferate further and faster on the combined network," Akonix spokesman Don Montgomery agreed. "The need for security rises as we now have a much bigger network and much more usage."
The alliance could turn up the heat on people using Yahoo IM. Microsoft's network is the most, as 62 percent of attacks in the third quarter this year were aimed at MSN Messenger or Windows Messenger, IMlogic said. In the same period, only 7 percent of IM worms went after Yahoo Messenger.
"Worms that are traditionally targeting MSN will also target the Yahoo users," Sakoda said.
America Online's AOL Instant Messenger dominates the instant-messaging arena in the United States, tallying 51.5 million users in September, according to research firm Nielsen/NetRatings. That compares with 27.3 million for MSN and 21.9 million for Yahoo.
Providing a secure IM service is top priority at Yahoo and Microsoft, said Terrell Karlsten, a Yahoo spokeswoman. "This priority is certainly extending to the interoperability between our two communities," she said. "We will certainly continue to innovate together and leverage our collective best practices to keep IM safe and secure."
Yahoo's statement was echoed by Microsoft. "Microsoft and Yahoo share a commitment to deliver IM interoperability while keeping consumer security, safety and privacy top of mind," Brooke Richardson, a lead product manager for MSN at Microsoft, said in an e-mailed statement.