'Make navigation joyfully surprising' is the first tip from Nielsen Norman's Kara Pernice's latest post. She works for Jakob Nielsen, so she knows what she's talking about. 'A challenging and unexpected navigation will exercise users' detective skills and thus train their working memory'. So that's it, I realised, that is why so many sites make visitors play hide and seek ... sites like ExxonMobil and Visa USA giving the little grey cells, and indeed fingers, so much practice scrolling and down and guessing where to click.
Plenty more ideas from Kara here: Use walls of text to encourage users to read more, make users go deeper into the site. Yes, yes, yes, all brilliant - it's a shame she loses the plot in the posts she writes when it isn't April 1st.