This excerpt taken from the SOHU 10-K filed Feb 26, 2009.
Wireless Value-added Services
We operate as a service provider to Chinas leading mobile network operators, offering a wide range of wireless products focused on entertainment, information and communications. These products are available to end users via a broad choice of technologies, such as SMS, RBT, WAP, MMS, and IVR services. We provide wireless services mainly pursuant to our cooperation arrangements with all of the three Chinese mobile network operators and their provincial subsidiaries.