Went on Wikipedia to find some more info http://en.wikipedia.org/wiki/Secure_Digital
and found an interesting fact.
"The signature “SD” logo was actually developed for another use entirely: it was originally used for “Super-Density Optical Disk”, which was the unsuccessful Toshiba entry in the DVD format wars. This is why the “D” looks so much like half of an optical disk."
All makes sense now, lol.