Examples: If you target Amazon EC2, you'll probably pull in euca2ools and use pv-grub, set up a default user account, and soon use cloud-init. If you target Google Compute Engine, you'll probably pull in gcutil and gsutil and a few other packages, use our account management by default, temporarily use our injected kernel, in the future use the Debian kernel with a very sane boot method (I'll definitely tell this list when the details are public), and also eventually cloud-init. If you target VirtualBox, it'd be like Compute Engine but with their guest additions instead of gcutil/gsutil (unless Oracle made them non-free), no cloud-init, and account management TBD. Vanilla Qemu/Kvm would be a hybrid of the previous examples.