When you softmod your Wii, the first thing you will do is run the hackmii installer, that will get the homebrew channel installed and you can also backup your nand. After that is done, you then move on to installing the good stuff that lets you load homebrew. Most of your homebrew runs from an SD card or usb device, very few things get installed to the Wii itself. I keep all my apps on the SD card and put backups from a USB HDD. To me it's a bit easier to take the SD card to my PC to install/update apps instead of taking the usb hdd to the pc every time I want to add or update an app.