While Matt Cuts said there's no keyword density, there still should be some metrics on what's better to avoid confusing google. I hope my question makes sense. We have a website which can potentially have about 800 words on the main page and 2000 words on 3-4 more pages. Or we can make a parallax website and put all of those 2800 words on one page. Does google have anything against 1-page websites? I couldn't find any info on it. Is there such thing as keyword dilution and maybe having too much text for Google to understand what it is I want to rank for?
I could only really speak from personal experience. I've ran 1 website which was parallax and the rankings on it dropped. In my personal experience Google still likes/prefers the separate pages, but that isn't to say no one could get it done... I just have found personally the individual pages are still best.
keyword density is one of the major downfall of sites. you try to make sure your keyword shows up enough, in the process you content seems unnatural. and this hurts you. focus on one keyword for a page and make sure your content is worth reading, this will get you a lot farther with Google.