ReBoot

I always wondered about this. It is kind of funny how the little details get so much attention. Also thanks for that wiki link about icons, it was interesting.

cecil has unique PID. It is coloured like rainbow...

groooovey!

I still like the icon from the evil dead game they played, It's black with a little skull in it...night of the living binomes o_O...ooooOOOOOOooooOOOOO, XD!!!!

hmmm... andraia's is different because she's a game sprite so naturally their icons would be different and as for the british binome? he confuses me too lol i think i like the idea of him being a guardian from the super computer although his motives are ambiguous...is he watching over bob? or maybe pearson (despite quitting the guild he still may know some code))

metallic gold colour and based on Back Up's head structure (looking like a huge brain) makes me assume that his function would be similar...i'm actually watching that episode now and i may change my mind lol but the black and white ones with the alternating triangles seem to be universal i think i'm changing my mind right now and i think maybe the writers were trying to emphasize that the systems to which matrix and andraia were traveling were far different from their own

okay so the normal icons are the black and white with the white and black triangles...the guardian icons i always thought were a gold colour rather than yellow so i figured that since they were "guardians" and therefore special (bob wasn't effected by hex's medusa virus implying his code was different) they merited this gold colour on their icon...the viral color added to the icon shows which virus has effected what PID (enzo's icon turned red and black when hex gave him a little part of her code)(megabyte's viral binomes had green and black) so to me the black represents a basic code present and the white shows a potential to add more code...
as for the different shapes y'all bring up a very good point that Back-Up's icon is different from the other inhabitants of his system so I can only assume that he's like an upgraded version of phong kind of like how computer programs see upgrades and look different and are better...the reason this is my conjecture is because they are the

Ray Tracer's icon is the Motorola icon with the letter M. I think it's because he's a second generation web surfer/ search engine.

As for Phong, there are other people that have a similar design to him. The search engine Maxine from "The Episode with No Name" has a metallic look, as well as Back-Up. Also, Hack and Slash have a metallic look. Neither Phong nor Hack/Slash have legs. Instead they move around with a ball.

In regards to Phong's icon, it could be because he is part DOS and part windows / linux. This website explains it better: http://reboot.wikia.com/wiki/Icon

Everyone else from Back-up's system had a normal reboot icon. So did everyone from every other system they visited (save for the Search Engines like Ray).

Back-Up's icon is different because he is from a different system. No one said all icons were the same.

Phong's icon is different because he is the keeper or the core.

The British Binome still boggles my mind.