serpens

Certainly you shouldn't conclude it was a bad assumption because I didn't know what MDD meant; I couldn't have helped anyway. And perhaps all the people who could help would know what it means. But there might be someone who would help who didn't understand the abbreviation and therefore couldn't. If I were asking for help, I would strive to avoid that situation. (I just checked, and MDD is in the glossary, defined as Modified Double Dip.)

Another reason i would try to spell out an abbreviation, at least the first time I use it, is so that someone in a similar quandary later might find the discussion. Of course, this doesn't benefit an original poster, but it seems like a nice thing to do.