Earlier quoted context omitted.
Run: sh | wget http://www...something.com/install.sh to install something automatically! Way too many projects do it, from my head: rvm and oh-my-zsh.
No worse than "./configure && make && sudo make install"
In theory, yes, `curl | sh` is the same as configure&make is the same as downloading your initial iso image and installing the system from it. In practice they have different risks associated with them.