Thank you for pointing this out!
All these three terms are now also widely used among Zoroastrians in Europe and the Americas.
"Mazdayasna/Mazdayasni" is especially popular as it has the same meaning as the Greek "Philosophia/Philosophers" which has a very attractive meaning to Western ears.
2010/1/20 Bahman Noruziaan
For the benefit of the newcomers into Zoroastrian studies or Zoroastrian community:
In our religious classes may years back in Iran, we, the young students were taught that we the Zoroastrians are called:
1-Zartoshtis (Zoroastrian) because we follow the teachings Zarathushtra
2-Behdin, because we follow the Good Religion (Dainya-o Vanghuya-o) , Beh means good in Persian and Din, means religion.
3-Mazdayasni, because we believe and praise the wise one (Mazda).
All these words, for the Zoroastrian community and a Zoroastrian meant and mean the same and are interchangable. They have been used with the same interpretation and meaning for thousands of years.