What do the different colors on the Aliases page mean? The ones I suggest are highlighted in silver, but others are green?

After some comparison, I'd say that silver means pending approval, and normal/green means approved.

Let's see: Green = character, Red = artist, Purple = series, & Blue = content. But I've never seen silver. o.o;

Go in the "Aliases" section on the menu. He's not talking about tags located in the sidebar.

Whoops.... I'll just go bang my head in the fridge door repeatedly now. >_>;

I've seen a few images with the tags colored wrong. It's no big thing, but it's a bit weird some times.

Hmm... yes I thought/worried that might be the case.

Now I am confused as to what aliases actually do... is it just for searching?

I had hoped my suggestions might clean/get rid of/change some of the tags in the "tags" section at the top of the page.

Aliases are just a way to "redirect" certain tags toward other tags. As with the example atop the Aliases page, say once Evangelion -> Neon_Genesis_Evangelion is approved, all pics tagged as Evangelion are now only tagged as Neon_Genesis_Evangelion, all searches made for Evangelion will return results for Neon_Genesis_Evangelion, and all further tag edits with Evangelion added will be converted to Neon_Genesis_Evangelion.