Pulldowns are most effective for alphabetized lists of items with known names, like countries, states, or products, because there's no thought involved. If I'm looking for VCRs, for instance, I can just scroll down to the V's.
But they're much less effective for lists where I don't lnow the name of the thing I'm looking for, especially if the list isn't alphabetized or is long enough to require scrolling. (p. 110)
...the Web experience is missing many of the cues we've relied on all our lives to negotiate spaces. Consider these oddities of Web space:
No sense of scale. Even after we've used a Web site extensively, unless it's a very small site we tend to have very little sense of how big it is (50 pages? 1,000? 17,000?). For all we know, there could be huge corners we've never explored. Compare this to a magazine, a museum, or a department store, where you always have at least a rough sense of the seen/unseen ratio.
The practical result if that it's very hard to know whether you've seen everything of interest in a site, which means it's hard to know when to stop looking.
This is one reason why it's useful for links that we've already clicked on to display in a different color. It gives us some small sense of how much ground we've covered. (p. 57 and note)
Imagine a browser extension that lets you specify how soon to revert links to the univisited color on a per-domain basis, instead of the global setting that Internet Explorer and Firefox provide. I would be all over that.