Can you trust user reviews? Tips to find honest evaluations

PCWorld recently published an article about user reviews in the iPhone app store and how some of them are planted. Wired actually had a screen shot of a job post offering $4 to anyone who would post a 5 star review of the SantaLive app. Just a few months ago a Belkin employee was caught offering payment for positive reviews, and Amazon’s Kindle 2 user review section are full of reviews from people who don’t even own the device. Yet, these days more and more people rely on user reviews when deciding to make a gadget purchase, especially these days when every dollar counts. So how do you know what reviews to trust?