The Ministry of Magic official site

And since 2007, many people too young then to read the books have become older and started them. Many people who were old enough but did not get around to it are now getting around to it. New people are being born every day who might someday wish to read and enjoy the books. A quick check at Amazon shows that the books continue to sell well--and I think it is a good bet that most of those are for people who have not yet read them.

As far as the movie goes, it has just recently made it to non-premium pay TV. Many many people who get their movies via cable or satellite and do not have HBO but do have more than basic cable/satellite are getting around to seeing it.

So yes, it is a spoiler to many people.

I've seen the first 6 movies, and am currently about 1/4 of the way through book 6. I happened to have already known about the death of that particular character, so your post didn't spoil anything for me, but I bet it did spoil it for some people here.

Some spoilers have become memes and catch phrases. Those new to Star Wars, for example, probably have no realistic chance of being surprised by what was the big shock to those of us who saw "The Empire Strikes Back" in the theater in 1980. For those spoilers that have not become embedded in pop culture, though, I see no reason we need to go around blurting them out.