Does the WD TV have proper support for 4:3 screens?

Hey!

I have an older 4:3 screen that I would like to use a WDTV with, does the user interface properly scale to a 4:3 screen, and can it display 16:9 content (letterboxed to fit the 4:3 screen) and native 4:3 content (full screen)  correctly?

Yes, it can.

The main issue with older sets is that some of the UI’s text and fonts are too small to read clearly on a small, low-resolution CRT…

So just to confirm, I can connect the WD TV (gen 3/streaming) to a 4:3 TV and play a 16:9 video file without stretching (with black bars up the top and bottom)? Please reply.

What about the Youtube service, can I do the same with videos from that?

Yes.  It will letterbox 16:9 content.

Not sure about YouTube.