It doesn't take a private eye or an investigative journalist to inspire a cynical stance on user comments. These online remarks and ratings are popping up everywhere. From restaurant reviews on Yelp and Citysearch to product comments on Amazon and eBay, consumers are bombarded with opinionated product reviews from everyday people -- just like you.

Or are they?

Recent news stories have showcased how these mushrooming comments aren't always legit. A recent New York Times article busted the online retailer VIP Deals for essentially giving away its Kindle cases in exchange for positive reviews.

It has become common for online retailers, blogs and other Internet-based media to pay for positive comments and reviews, said Cleo Kirkland, a digital marketing consultant with Blue Fountain Media in New York City. He said marketers commonly hit up sites such as Fiverr and Amazon Mechanical Turk, in which workers make themselves available to do various low-cost tasks, including writing positive reviews for a fee.

"I rarely trust comments, especially if they are mostly positive," Kirkland said.

He offers these tips for determining whether a review is real or should be dismissed as an opinion-for-hire:

Throw out the very positive and the very negative to get a good consensus of reviews. What do most of the three- and four-star comments say? Do some five-star comments also mention negative points? "Look at the outliers, then decide," he said.

Check out the reviewers. How many connections or friends do they have on the site? Do they have fleshed-out profiles or just the basics? Does the reviewer give all five-star reviews? Does he or she actively engage with other reviewers? University of Victoria researchers found that paid posters make lots of new comments, but they don't engage in discussion.

Google the review itself. University of Victoria researchers also discovered that half of paid posters post every two and a half minutes and cut-and-paste the same content multiple times.