"I Say Yeah!" is a single released by all five of the signed artists of Neosite Discs, a sub-label of Ki/oon Records dedicated to R&B, hip hop and reggae, to celebrate the label's 10th anniversary. The single received minor popularity, entering the chart at #8, dropping to #20 in its second week, and staying in the charts for seven weeks. The A-side was the opening theme for NTV's Music Fighter in October.
A live concert was held at Shibuya-AX on October 27, 2006, to celebrate the 10th anniversary, with all of the participating artists performing the A-side from the single as well as a number of their own tracks.