I don't use ignore but I would like a function that lets me tag other users and changes their post background color from then on (for me only).

Kind of like how the OP posts can be orange.  I'd like to be able to create a tag list (say...of DU plants and trolls for example) and when users I've tagged post, their posts show up with a yellow background or something.

Ideally I would be able to have several tag categories and set each category to have its own background color.  I might make Mod and staff posts have a blue background for example by creating a tag list of mods and staff.  I might create a friends list that shows those users posts with a green background.