Well, for me, defragmenting something would be the same as formatting, except formatting is defragmenting and changing the format of the drive. What format is your memory card? NTSC? FAT?
Could have sworn they were different things. Because Windows doesn't give you the option by default to defrag flash media but you can format and even with digital cameras there is no defrag option but you can format. I guess because flash media has no moving parts? And my card is fat or fat32 depending on the size (and compatibility).