[tjohns]

IPP's got a few problems, especially when it comes to phones/tablets or other mobile devices:

- IPP requires unique drivers for each printer. Some mobile devices (Chromebooks and iOS, I believe) don't allow installing drivers.

- IPP requires that you're on the same LAN segment, or that you punch a hole through your router. That doesn't work very well when interacting with foreign printers, and punching a hole through a router is too complex for many home users.

- IPP is limited to HTTP Basic/Digest auth, which isn't user friendly or secure. The traffic's also unencrypted. (And SSH isn't user friendly enough for home users.)

(Disclaimer: I work for Google, but not on Cloud Print.)