Are you talking playing tunes or accompanying your (or someone else's) singing?

DADGAD is a tuning, not a key. You don't have to slavishly follow what someone else did with a song so, if you think a particular song would sound good using DADGAD, go ahead and try it, irrespective of whatever tuning was used by the writer or on the CD you heard it from. Part of the fun of working out 'new' songs (new to me, that is) is trying different tunings and chord inversions to get 'The' sound that I like. Sometimes DADGAD works, sometimes something else is better (including standard tuning).

There's no law that says if **(insert your favourite artiste here)** did a song in a particular tuning, that's the only tuning you can use!

DADGAD's a nice alternate tuning for a newbie - you can put your fingers anywhere (almost!) and it will sound OK.

EXPERIMENT!