I don’t know of its use outside of Hungary, but here, as the quote of Halmos suggests, the tombstone is traditionally used in print magazines as end of story. We have adopted it to the web on the Weblabor magazine, where it stands at the end of all blog posts, so the reader knows if it worths to open the story on its own, or the excerpt on the front page was the whole story.
We had a problem with U+220E END OF PROOF though, as in most fonts it is a rectangle, while in traditional use it is almost always a perfect square. So we decided to use U+25A0 BLACK SQUARE instead, which has its own problem since it really is oversized for this usage, so we had to mark it up and scale it down. An example (the square stands on its own line because of the limitations of our implementation for the time being; it actually should be the last character of the closing paragraph): http://weblabor.hu/blog/20120801/magyarorszagi-web-konferencia-2012 I’m curious whether this character would be eligible for disunification, introducing an END OF STORY character for traditional journalistic use, based on the fact that END OF PROOF seems to be consistently differ in shape, and the precedence of many symbols also in mathematical use encoded separately.
