First of all. I'm happy you found the post to be beneficial.

A curator and a moderator could be the same person, they could be different persons as well. It all depends on the administration of the community.

There's nothing special about the moderator's account and a curator's account on Hive. So, in some community, you may notice that one person serves both roles. In others, these roles are divided into different users, which sometimes, in the background, the moderator may be the one controlling the curation account.

However, curators usually have big HP (most of them are whales), so most communities for safety will have moderators separate from curators so they send moderators to curate in terms of checking posts that are worthy of curation, then the moderators will share feedback to the curator who now votes the posts.

For spam posts. Maybe I'll cover this extensively in a later post. But spam posts are one or a combination of these:

1. They are unsolicited and unwarranted. Imagine going to Leofinance to talk about make-up, that's spam.
2. They are overly recycled. This is common in the comment section. Where you see some bots make the same comment over and over again.
3. They are usually of low quality.

Basically, once a content, be it a comment or post is irrelevant to where it is being shared and unsolicited, it's spam.