Arabic and Hebrew, on the other hand, are primarily RTL, and this does carry over to UI conventions. Menus might be laid out differently there.
Many soba restaurants use vertical text written right to left because it gives a sense of old times. Higher end traditional-style restaurants do this too.
Family restaurants and anything with western food is pretty much always written left to right.
It's also very common to see street signs (notably "construction ahead" and "beware of __" signs) using vertical right to left text.
Well books are generally vertical and right to left. Generally periodicals as well, but the internet has made more things left to right.
(I don't know if I agree with the comment you're responding to, by the way.)
It's irrelevant for computers because text on computers is basically always left to right though.
This isn't true in Japanese which is what limteary was asking about.
The primary exception is where the context of the writing itself implies a direction, e.g. text on the passenger side of a bus, or on a directional sign pointing to the left, may be written right-to-left so that the text "flows" in the same direction as its container. This would never be used for a longer text, though.