Microsoft is in the early stages of doing their "embrace and extend" deal on RSS feeds. They've renamed them "web feeds" and will use "enhanced", non-standard extensions.
However; In the interest of cutting user confusion, they are going to use the exact same icon Mozilla and Firefox use. They met with people from The Mozilla Foundation and decided it was in everyone's best interest. So the little orange rectangle lives on. MS may indeed choose to put other text on it, but we'll all have no trouble finding it and I for one am happy they've done this.