Basically it means whoever typed it was copying and pasting or trying to look up a charmap or something silly, not actually typing Japanese.
The size doesn't actually make much difference, but they're different Unicode characters and you can't type the wrong one by accident.
-
-
-
You don't actually have to be able to tell them apart visually because which one is intended is obvious by context. Like I and l in English.
- Show replies
New conversation -
Loading seems to be taking a while.
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.