"I am telling you about it."

Translation: Jeg fortæller dig om det.

[Martin_Petrera]

Does "om" mean about?

[Jay709846]

Ja.

[Joan.Co]

when do I put Du or dig??

[sumuenkeli]

Du is used if you (singular, of course) is the subject of the sentence, while 'dig' is used when 'you' is the object of the sentence.

[Jay709846]

Is that 'if you are the subject of the sentence'? XD

[Jay709846]

I think is that this sentence is a bit too long to register.

[Bluthund]

Why is "jeg fortæller dig om DEN" marked as incorrect?

[sumuenkeli]

It should be marked as correct, since both den and det mean 'it'. I don't know why it's marked as incorrect, maybe it's an error made by duolingo? I'm not a native speaker though, so if I am wrong, someone correct me.

[Domburt]

That seems to happen to me a lot too

[nemoequus]

You only really use "den" in Danish if it is clear what you are talking about. "HundEN er sød. Jeg fortæller dig om DEN"