Are these sorts of sites just a fad? I have read reviews about "when they are done right" but usually these sorts of theories focus on the extremely good cases - like where a website is doing some sort of special theme or "story telling."

I mean just for regular sites. For me, I don't like scrolling, because I usually want to get back to another part of the site, and many of them do not have menus for each section, or the section that a menu link takes you to - is not full screen, or extended past my screen anyway. I have to scroll, within a scroll site! And, I dislike clicking a button, to go to a menu to go back to a section that was close to where I was anyway.

It might just be that I am a minimalist, and these "scrolling" site usually get fluffy and background image intensive.

I think it depends on what the site is for. Sites with no need to share lots of info may benefit from a one page scroll but I agree that making them to long may be a problem but that would still be up for consideration of the intended viewers.

I think this is correct, one pages had issues way back with SEO but not any more, and all I see is more of them.

In fact the multi page sites, unless they "need to be" multi-paged look kinda clunky these days LOL