In a cost-cutting move, Twitter will no longer send its U.K. clients updates via text messaging.

Users of the popular micro-blogging site will still be able to send updates, or tweets, through SMS, but the company said its agreements with British carriers made sending outbound texts too expensive.

"Even with a limit of 250 messages received per week, it could cost Twitter about $1,000 per user, per year to send SMS outside of Canada, India, or the US," Stone wrote. "It makes more sense for us to establish fair billing arrangements with mobile operators than it does to pass these high fees on to our users."

U.K. users were encouraged to receive Twitter updates through the company's mobile site, e-mail enabled phones, or through third-party applications like Twitterific. Twitter also said it is working to establish more local numbers around Europe to make the service more accessible.

Users in the United States, Canada and India will not be affected as Stone said the company has "sustainable" billing agreements in place.

"Our goal is to provide full, two-way service with Twitter via SMS to every nation in a way that is sustainable from a cost perspective. Talks with mobile companies around the world continue," Stone wrote.

Twitter is a micro-blogging service that lets users send updates up to 140 characters in length. It launched in October 2006, and has exploded in popularity, particularly with high-profile technology personalities.

The service has even drawn the interest of companies and organizations like Zappos.com, Comcast, Dell, and NASA, which send "tweets" to keep their audiences informed. But the company has seen multiple outages as it struggles to adapt to its growing user base, and many still question if the service will be able to eventually produce revenue.