I don’t recall ever hearing about it. Far away in a different country.
I was 15 at the time, living in the suburban Detroit area, and I don’t remember ever hearing about it. I did follow the Iranian hostage crisis very closely in the news the entire time until it was resolved (Reagan to the rescue! 
), so I was interested in, and aware of, current events in the news in general. Maybe, as NDP says, the Greensboro massacre story just got eclipsed by that for me.
Them I’ve heard of.
Yes. Have you met 21-year-olds? They are inherently oblivious, even to stuff that immediately affects them, like what day classes start for the semester. Something that happened before they were born, even if it was in their local community, doesn’t even rate.
(And I, a reasonably well-educated American born in the mid-1970s, also had never heard of the Greensboro massacre, so I’m not sure your perception of its historical significance is accurate. I’m sure it was big news at the time, but most things that were big news at the time slowly fade from public consciousness over the years, unless they change subsequent events or perceptions in a big way. In this case, the vast majority Americans in 1979 already believed the Klan and neo-Nazis were very bad people, so I doubt this would have had much impact on perceptions, and I don’t know of any long-term impacts.)
At this point, it appears that 17 people have clicked on the initial Wikipedia link, which … says something.
I consciously chose not to click on it, lest I tacitly admit that I’d never heard of it either 
I was just a few months old when it happened, also in the Midwest. I am not aware of it either.
I knew about it, but I don’t think it is necessarily common knowledge among Americans, probably because the victims, as Communists, weren’t particularly sympathetic.
I’m mildly surprised that someone from Greensboro would never have heard of it, but I guess people in that region learn to not be too curious about their history.
Not surprising. Most American adults don’t remember this either.
Don’t feel too bad, folks. I was in college then and I’d never heard of it, and I’m interested in American political history.
I didn’t have a TV. I kept up with the news by reading the newspaper at the university library. If it was a weekend, I missed the news. The Greensboro Massacre happened on a Saturday, so the following day I didn’t read the paper. Then the hostage crisis exploded and nobody could think of anything else. A couple days later there was a terrorist incident on my university campus: an American with a gun held the switchboard operator hostage for hours, demanding a list of all the Iranian students on campus. So that dominated the local news.
We didn’t have Howard Zinn running the media, so news involving American Communists didn’t get far. To have this flung in our face now by MM is a reminder of why Zinn needed to write A People’s History of the United States, because this kind of news had been suppressed all along.
I was a 16 year old California High School student who watched the evening news. If I heard about it, it was quickly forgotten. It’s like all of the California serial killers at the time. I listen to stories on podcasts about body dumps, killers’ homes, abduction sites, etc. that were less than a few miles from where I lived, worked or went to school. I don’t remember hearing about any of that at the time. I probably did, but I had more important things to think about.
With just “Greensboro Massacre”, it didn’t ring a bell. With the info of the KKK and the CWP being involved, I remembered it.
I’m pretty sure I learned of it from a documentary or a news analysis done long after the fact. I’m not sure if I learned of it before or after I was 21.