The answer is NO!
With great astonishment I found out that in german you should NEVER put a comma after the salutation in your letters and e-mails.
I remember I was in a german course and the topic was writting e-mails (formal or informal). And someone asked “should we put a comma after the salutation?” I thought “what a detail…so unimportant!”
How mistaken I was.
Many of us were so amazed and so sure we saw commas in our correspondance and we promissed to go back home and check it out. I did that the next day with many of the e-mails I received at work. Surprise! I couldn’t find any comma. Not even a single one but in the e-mails that I sent…
Since then, when I end my e-mails I alwas put a comma after the salutation… then I remember and delete it. 🙂