Today I attended a board meeting for an organization I'm in. Board members traveled from various parts of New York State for the meeting, which was held in a county park (under a tent and by the lake). The park has a web site, with driving directions, but not with detailed directions of how to get to the various pavilions, etc. When you get to the park, there is no information at the entrance that will help you. (And no one to ask a question of.) You have to either "know" or be willing to drive until you find the right location.
What does this have to do with digital libraries, for example? Is your service obvious? Do your users understand what to do? Where to go? How to get a question answered? Could "signs" be useful?
And like getting to a distant location, once your users get "in" do they know how to get "out"? In other words, is everything obvious? If not, find ways to make what is obvious to you, obvious to your users. They'll thank you for it with fewer questions and less frustration.