Who isn't getting into the mobile e-mail business these days? Nokia became the latest entrant earlier this month with a new client-server solution integrating back to Microsoft Exchange, but the options are becoming dizzying. Although just two years ago Research in Motion had a virtual monopoly on push e-mail, new start-ups like Good Technology, Seven and Visto are joining established industry players like Microsoft and Intellisync in challenging RIM's dominance. In some cases, they appear to be succeeding. While almost every carrier in the U.S. offers some kind of BlackBerry device on its network, most of them are coupling RIM's devices with handset-based solutions of their own. Cingular sells GoodLink push e-mail over its smartphones and PDAs and offers a more static yet cheaper e-mail solution through Seven. Sprint is even more aggressive. Its new subsidiary Nextel is incorporating Visto's Java push e-mail client onto the majority of its data-enabled phones, which means a potential 7 million of Nextel's 15 million user base could have push e-mail. Interestingly enough, all of the activity seems to be fundamentally changing the e-mail business. That's why RIM can't be written off. It still has a lock on the high-end push e-mail market where service costs $50 per month and up. The new services, however, are more handset-agnostic. They're targeting the mid-tier user. And the sales relationship is shifting from the vendor direct to the enterprise to the carrier direct to the user. In fact, the shift is so profound, we're starting to see shake-up in the industry. Good eliminated a fifth of its staff positions last week representing the firm's new focus on carrier support rather than enterprise sales. As more players like Nokia and Microsoft develop their strategies and carriers become aggressive, the mobile e-mail industry is going to look a lot different from what it does today.