Ian, it's true that people don't use them, but the reason is they're not really post icons: they're mood icons, there are only 14 of them and they don't add any additional information to a thread.
However, if you add your own post icons (and that's the whole point, they can be very useful)
Mat, "post icons being deprecated" is not something I made up, it's an answer I got from one of Invision's admins.
Your pathetic answer demonstrates that you didn't understand a single thing about the video.

Post icons are still there, yes, but in IPB 3, they do not appear on the topic list when you post a topic unless you modify a couple of .php files, and the fact remains the invision has said so already, they don't think it's a useful feature.
As for choosing youtube or not, you do what you wish mate, I'll keep doing what I want. Got any problem with that?