I remember that Word's German spell checker started quite early to only accept the spelling "E-Mail" as correct. This was at a time when emails were fairly new,

I remember that Word's German spell checker started quite early to only accept the spelling "E-Mail" as correct. This was at a time when emails were fairly new, and spellings like "eMail" were also common. (Though not "email", as nouns are capitalized in German.) I'm pretty confident that Word played a significant role in "E-Mail" becoming the canonically accepted German spelling.