The 'thanks' feature has been used for some time on this site however it was removed during the recent upgrade to vb4 - it was not compatible at the time. The feature was also only used on certain forums and when I installed it just now I added it to all forums. It is not meant to be a replacement for the reputation system just another way to give members credit where credit is due. The reputation system that we used was also not compatible when we upgraded and is still not supported on vb4, but when it is, it will come back as well.
I do feel that the 'thanks' fonts needs to be smaller and for it to take up a bit less space so I will work on that.