The death of the paid text message

The smartphone boom is a mixed blessing for wireless companies. While the devices have boosted data plan sales considerably, they are threatening to kill another revenue stream dead in its tracks: text messaging.Dozens of smartphone applications offer free text messaging services, which allow wireless customers to send and receive texts by piggybacking on their existing data plans. That means people who download those apps -- such as GroupMe, Google Voice, Disco, Beluga, Kik and WhatsApp -- are able to bypass the expensive texting plans offered by wireless companies.Whats more, an increasing number of free text messaging services are being baked into the smartphones themselves. Research in Motion (RIMM) offers BlackBerry Messenger, which allows BlackBerry users to text one another over their data plans. Apple (AAPL, Fortune 500) plans to introduce its similar iMessage app in the fall for the iPhone.And Verizon Wireless embeds Skype onto every one of its smartphones. Skype bought GroupMe on Sunday, in a deal valued at around $80 million, according to several reports. Since Microsofts (MSFT, Fortune 500) deal to buy Skype will likely close in the coming months, GroupMe could soon appear on every Windows Phone device.