I'd like to add some content to my site that Google crawls but that visitors don't see. I've done some testing with display:none and visibilty:hidden, these don't appear to work and Google ignores them - although quite how that works I'm not sure as there are many innocent uses for that. Googlebot can presumably figure out the intended use by rendering the page as close to 'normal' as possible.
Has anyone done any benchmarking on this to see what "works"?
(I'm not talking about content stuffing, that's a bit 2004)