So, just about every culture practices some form of ancestor veneration. Everything from researching genealogy, building shrines to their ancestors, to just decorating graves, it's all a type of veneration. The extent in which people do this depends on the culture, religion, and family traditions.
In Heathenry, ancestor veneration is central. What, exactly, "veneration" means varies by person, but just about every Heathen does something to honor their ancestors. Some people use the term "worship" to describe their dealings, and some people abhor the term because, from my understanding, it puts the ancestors on the same level as the gods. For the most part, though, I think that's kind of a misunderstanding. I've never come across anyone who worshiped their ancestors in the same way as they worship the gods.
While I was looking up ancestor worship info, I came across the blog heathenfolk. The author talked about how there's three versions of ancestor worship in Heathenry. I'm not entirely sure I completely agree with what he says, but it's still an interesting...