immer mit komma. geht für alle sachen, die vorangestellt werden wie z.b unfortunately, actually, therefore, addiotionally, although, however etc.

I don't think there is a hard and fast rule; it depends, rather, on the ususal considerations for such adverbial phrases:
Does it modify the whole sentence?
Would its absence significantly alter the meaning of the sentence?
Is there a break in continuity?
Is there a potential ambiguity?

In most cases these considerations would make a comma neccessary, or at least possible.

I might omit the comma in a sentence like:
"In general I would put a comma after such adverbial phrases, but this is just a personal preference.

Thanks, very interesting!

@LondonGirl: The although doesn't really require a comma except for cases where one omits the respective subordinate clause... or would you disagree?