I have just had my deal removed and as usual I get no feedback from the mods as too why.
A member did post that it was a duplicate but I asked him to provide the link and I would get it shut myself (not sure if he did as my deal had vanished within a few minutes). I had searched the whole site for EON and power plug (which the deal was for) and couldn't find anything posted within the last week and anything later than that was expired and not the same deal.
As others have said, it would be nice if you could let people know why you have removed a deal. Leaving your members not knowing isnt the best way to run a forum IMO.
I know that duplicate posts can get posted by mistake but at least let people know and provide a link so they can feel a little better treated than simply removing the deal with no communication!