
On July 1st Nintendo is implementing large coin drops for completed surveys on many of its products. For instance the DSi drops from 160 to 100 and eShop games from 10 to 5 coins. For a complete list of the changes, check out the source link from Nintendo.
Systems

3ds

Wii

Dsi

PS- Don't forget that 2 year old unused coins also expire on the same date.