The Thanks option is cool. 🙂
Actually, I have implemented the thanks mod first on Yaf 1.9.3 RC2. You can find out more Here .
And here is the implementation on yaf 1.9.3 Final. You can download it form Here .
Anyway, The latest svn build has several bug fixes and is improved in performance very effectively so I recommend you to upgrade to 1.9.4 when a stable release has been published.