Jakob Nielsen - Feature Richness and User Engagement:
"Typically, when new prospects first visit your site, you're simply one of ten sites on the SERP [Search Engine Results Page]. The only way they'll shortlist your site is if you can convince them in two minutes.
Thus, websites should have almost no features: focus on the words.
To determine how much complexity you can afford in a user interface, you must analyze user engagement levels: Do they care deeply, or do they just want to get something done as quickly as possible? Typically, users care less than you think! You're not important to them. This is one of the main reasons companies need systematic usability studies: to make explicit the fact that outside customers don't find your design as important as you do (because you work on it all year)."