Ask HN: Why don't we indicate internal vs. external links?

Hypertext is great - but how come we don't (in general) indicate whether links are internal or external? Sure, you can mouseover a link and check the status bar at the bottom - but that's not very obvious for your average user.

Why not visually indicate whether a link is internal / external with a glyph (::after) or a separate color (maybe orange instead of standard blue?)

Is anyone out there doing something like this? Do you think it'd improve the web experience?