For a list of commonly asked questions and answers visit FAQ.
The FAQs I encounter most often are:
Importing from Google Scholar - see under Hot Topics in Support and Services
Import 2: re Mac users and Firefox, instead of IE or Safari
QWYW 56: re Mac users and Pages 09 software
QWYW 60: re Word software and missing EndNote tools / toolbar
Styles 5: re Journal name abbreviations or the full journal name