It can be used either way but it carries a different meaning
Also [pause] ich werde jetzt gehen.
This is kind of concluding some discussion that has taken place before but it doesn't mean that my going is directly cause by whatever has been said before also. I am hesitant as to how to translate that but my pick would be
All right [pause] I'll leave now.
There is also a version without comma.
Also ICH werde jetzt gehen.
Also DAS finde ich nicht so gut.
In these sentences you will usually have a somewhat strong stress on the word that comes right after "also" and it has no "causal" connotation whatsoever. It is more like "for my part" or simply "well".
Well I for my part will leave now.
Well, THAT I don't fancy that much.
And then finally, there is the conjunction. This is indeed introducing a consequence, very much like the English "so" does.
Also bin ich gegangen.
So I left.
