I commonly browse all by new, and I block users who crosspost any given article to more than one other community. To me it’s almost always a sign that they actually don’t care about the topic or contents, but instead their own post count and user recognition.
I always feel a bit weird about crossposting myself for this reason. I do it mainly with the hope that more people will see the community I posted from, or to add something to a community that I want to see grow. But I don’t think I ever posted something to more than three communities, and everything I’ve posted so far had been made by me.
Yeah, I do also feel like there’s a fine line. I personally reserve it for communities I’m active in, and trying to nurture naturally. And again, only one crosspost at a time.