Absolutely not; you do not sound stupid at all. It's a valid question, one which every single one of us has asked at one point or another.
A DD (or Daily Deviation as it's called) is special recognition DeviantArt awards daily, to a few carefully selected members whom they feel their artwork should be brought to the attention of the community at large. It's a very high (and coveted) honor. ! ^^
Did you know that anyone can suggest a daily deviation? If you see a wonderful work - or gallery, which you feel worthy, and that you think others might enjoy as well, just make your suggestion to the appropriate CV (community volunteer) who handles it.
Click the link below if you are interested and read; scroll down and choose the appropriate volunteer whose position matches the genre of art you wish to suggest.
Also learn about the DD Suggestion Drive which we hold from time to time in the following link.
ddsuggestiondrive.deviantart.c… (The Group Link)
I hope this was helpful.