Victor David Brenner hid his initials, when the chief engraver found out he had them on the Lincoln cent he ordered them removed from dies.
The public reacted negatively to it. They ended up back on the obverse at the base of the bust in 1918.
Oddly coincidental, I found a 1909-S a couple of weeks ago metal detecting but I couldn't for the life of me get a VDB to grow on that reverse... :-) (still worth about $50-$75 though!). One of my forum associates got an 1909-S V.D.B. in Vallejo earlier in the summer, one of the perks of west coast detecting is you get a LOT of -S mintmarks and they are often the tough ones.
Interestingly enough, Brenner's initials are still on the obverse of the penny on the bust's bevel toward the bottom of the coin...
It's just his large initials on the reverse that created such a firestorm...