that's technically two riddles, but I like sphynxes, so:
1: there's always email
2: the cloud is shorthand for "we have so many computers with so much space all over the world that we can create big piles of computers that just act as go-between storage for your files"
that's lengthy, so "cloud"
also "cloud" sounds cool and light and fluffy
"technical infrastructure" is too vague, and "other people's computers" is a gross oversimplification