Standard message and data rates may apply?

[Sam]

Just got a Twitter. Hah. So. What the hell does that mean? I have unlimited texting, No internet though. And, I have Sprint. Will it charge me?

[Tymme]

Because you pay for an unlimited messaging plan, you won't pay for sending or reciving messages from Twitter's shortcode.

This just puts the cost liability on your side- if you dond't have unlimited texting, for example, each message from Twitter would cost against your message limit (or cost you money if over that limit). Same if you have a limited data plan and use the mobile apps.

(It's essentially saying "you don't pay us to use Twitter, but you do pay your phone ocmpany to use your phone services".)