Hey there - thanks for the nice comments!

As has been pointed out, the normal functioning of the memory card won't be affected as we're using an independent partition, so there's no problem with unmounting. It shouldn't be removed from the device, of course, unless you revert the changes first. With the script I provided, this can be done painlessly.

And yes, it can be combined with the swap. I recommend a swap file instead of a swap partion since we already created a new partition. While you could create a third one, it's probably better to simply create a swap file on the new partition, with a big memory card you'll have more than enough space. Then you can always change its size by recreating the swap file, that's easier than repartitioning and resizing a partition, so you get more flexibility. I'll add that information to the Wiki page soon...

The internal memory is still used for everything not swapped out onto the memory card. While you could move pretty much everything onto the card, I only use it for home directories and configuration files. If everything were to be put on the memory card, you'd lose the ability to instantly restore the device to your customized working state after reflashing, since then you'd have to update the files on the memory card as well. It would be fun to investigate a three-partition-setup: The first partition as the normal memory card, the second partition for home directories and configuration files, and a third one for all of the remaining stuff. So you see, there's still a lot of room for further improvement!