Default [Q] Gophone data plan

hi guys,
Does anyone here uses the prepaid $50 unlimited Gophone plan for Vibrant?

http://www.wireless.att.com/cell-pho...k=1-007FTV-0-2


I looked up the Webpage of Gophone phone plans. and under the column of $ 50 unlimited plan it says it is unlimited however I can not understand the footnote below.

"Smartphone users must purchase a data package to use data services on eligible plans. Pay–per–use data is not available with Smartphones."

Does that mean that the prepaid $ 50 unlimited plan, has another separate internet data price?