In 2010 it was decided by Nichiren Order of North America that Nichiren Shu priests in America would use the title of Shonin 上人 at the end of our Dharma or priest name.
Previously we had been referred to as Reverend which we added to the beginning of the name.
Some of the reasons for this change were; other religions use titles that are specific to their traditions such as Imam for a Muslim, Rabbi for Jews, Roshi & Rinpoche for some Buddhist lineages, also the word Reverend was viewed as too closely associated with Christian traditions and was somewhat misleading in the context of Buddhism.
In Japan priests in our lineage are referred to as Shonin. Since we have a title that is understood in Japan and there is the precedent in other religions for using culturally specific titles it was decided to adopt the use of Shonin.
It should be pointed out that cultural differences apply if one is to follow proper etiquette and there are differences between Japan and the United States. In Japan one would never refer to oneself by any title. So in Japan I would never introduce myself as Ryusho Shonin. But when others are introduced by oneself then the title is applied. Here in the United States it is acceptable for one to introduce oneself and append a title to ones name. So in the United States it would be acceptable to introduce myself as Ryusho Shonin.
It was decided that we would use a comma to separate the title from the name, though that is subject to some further changes. But we are trying to conform to standard acceptable and universal methods that Americans would easily recognize.
Finally it should be noted that the Shonin used as our titles is not the same Shonin used when referring to Nichiren the founder of our order. The sound is the same but the characters as written in Japanese are different.