My web "home" page is simply a long list of URLs I mght want to visit. These are grouped by category, such as all programming pages of interest, all blogging pages, etc. My home page has over three hundred items, and I often have to search it.
At any given time, I use about a dozen of the links, but the particular dozen changes over time. It's easy to scroll through my home page to find the items I'm currently using, they are all a different color to show recent access. But why don't I take the few current ones and copy them to the very top of my page?
It would be very efficient to keep my most common webstes at the top of the page, but I don't. And I think the reason is, that I'm doing something else that's pretty efficient for me, and efficient for a lot of other people as well: I have a spatial memory for where my favorite web pages are, on this long list. I can usually find any specific one quickly. If I kept moving common items to the top of the list, I would never develop any feeling for where they are in the overall page. This spatial memory of where my favorites are is important to me.