Steps taken by Yahoo to safeguard its Yahoo Messenger instant messaging (IM) service from spammers are also disrupting the legitimate use of the popular Trillian application, a problem that had been foreshadowed in recent weeks. Trillian is an application made by Cerulean Studios that lets end users manage multiple IM accounts from a single IM console in their PCs.Steps take by\u00a0Yahoo\u00a0to safeguard its Yahoo Messenger instant messaging (IM) service from spammers are also disrupting the legitimate use of the popular Trillian application, a problem that had been foreshadowed in recent weeks. Trillian is an application made by Cerulean Studios that lets end users manage multiple IM accounts from a single IM console in their PCs.The major IM providers, such as Yahoo, AOL. and Microsoft, haven't enabled their systems to interoperate. This means, for example, that a Yahoo IM user can't send a message to an AOL IM user. Thus, users normally end up connected to several IM networks simultaneously, having to toggle among each service's IM management software, depending on whom they're communicating with.Software such as Trillian's doesn't solve the lack of interoperability but alleviates the inconvenience by establishing a single IM console from where a user can send messages to others in a variety of IM networks. Thus, for example, a user can have Yahoo, AOL and Microsoft IM buddies all listed in the Trillian IM application. There are other software applications available that perform similar tasks as Trillian's. However, Trillian, with about 940,000 users in the U.S. in July, is the most popular software of its kind, according to market researcher ComScore Media Metrix.Yahooupgraded\u00a0its Yahoo Messenger service in June by adding features designed to prevent IM spamming and gave its users until Sept. 24 to upgrade to this new version. The problem now appears to be that the new version of Yahoo Messenger doesn't play well with the Trillian application, something that had been expected. Cerulean Studios didn't immediately reply to an e-mail request for comments about this matter, but a message on its Web site acknowledges the problem and says the company is working hard to resolve it.A Yahoo spokeswoman declined to address the specific difficulties Trillian users may be facing, but acknowledged the upgrade could disrupt third-party software and services that aim to interoperate with Yahoo Messenger. "Our primary goal for the update is to prevent spammers from spamming our users. If this upgrade affects the way in which other services interact with Yahoo Messenger, it is a by-product of our efforts to protect users from spammers," said Mary Osako, Yahoo's director of communications.Yahoo believes its users will appreciate the spam protection, even if these efforts cause other inconveniences, she said. Moreover, Yahoo is receptive to talking to other companies "that share our goal of opening IM communications in a seamless, secure and convenient manner." She couldn't say, however, whether Trillian makers had contacted Yahoo or whether the companies were collaborating to restore Trillian's interoperability with Yahoo Messenger.Analysts have pointed out that IM service providers have been unwilling to establish interoperability among their members in order to hold on to them. Moreover, IM service providers value the real estate their IM software establishes on users' machines because they can use it to beam ads and promote other services. A software like Trillian, for example, allows users to access the Yahoo, Microsoft and AOL IM networks while bypassing the ads and pitches these companies beam down to their computers.