I have an idea of a broad topic. I want an overview of my topic. I need to narrow it. I want a small number of relevant hits and an idea of what's in each document before I go to each page.
Hits have excellent summaries.
I want quality, evaluated sites that have reviews and ratings because I have limited time. I need to do a pinpoint search because my terms are narrow. I have common keywords that probably appear in many documents and should make my search specific. Fast, powerful, with ranked results and many options for defining a search. I have common keywords in a phrase like New in New Orleans or A in Vitamin A that cannot be ignored.