Shinjidude said:
English doesn't convey length distinction
I actually thought that was what adding an "h" would do; compare "a" to "ah" for example...(or in this case, "o" and "oh")
Also, as for the Danbooru = Danbohru argument, I've seen instances in Japanese where "おー" was rendered from "おう"...
("Danbouru"?)