In throwingks' floating post:
"Currently, there is no way to backup your own cartridges or ROM files"
...but "Discussion of ROMs is ok, as long as you don't talk about the downloadable version."

I don't get it. What's the difference between the real cartridge/ROM and the downloadable version?

not much other than one is allowed to be discussed on the forums and the other is not...

you arent allowed to discuss a downloaded NDS rom for the same reasons you cant discuss downloaded xbox games, or anything that was obtained in a way other than from your retail/legit copy that you own.

Oh I get it, thanks.

However that sentence was probably the worst way of saying it.

eh.. ask a stupid question, dont expect a well thought out response :/

and back-upping is possible, with the neoflash mk2-3 and als the neo2/3 carts bij neoflash

There's also an older homebrew app that allows you to backup your DS carts. Forgot what it's called.