T-Mobile said the rate change will only apply to mobile aggregators--the companies that act as middlemen between marketers and wireless operators--and not companies that have direct relationships, including Twitter and Facebook. (Twitter also confirmed it hadn't received notice of any text rate increase from T-Mobile and has direct deals with all U.S. carriers.) That means no "Twitter tax."
The carrier also said in a statement that aggregators have always been charged messaging fees and that any restructuring of business agreements with them shouldn't' t be characterized as a new charge or "price increase."
SMS providers including 4INFO and other entities had strongly criticized the T-Mobile fee and SMS-based search provider ChaCha Thursday threatened to dump T-Mobile from its service. Verizon two years ago backed off a plan to charge to add a three cents per-message charge following a backlash from text companies. As it stands now, T-Mobile will go ahead with the $0.0025 charge next month.