User-generated ratings and reviews site Yelp was recently featured in an article in the East Bay Express that raises concerns about Yelp’s practice of deleting or reprioritizing user reviews.

The article has anecdotes from local business owners who tell of Yelp sales reps offering to delete or bury negative reviews if the owner signs up for Yelp’s ad program (at around $600/year). Some owners also recount that positive reviews of their business were removed from the site after the owner refused to buy ad space.

While these allegations are unsubstantiated, they do raise an interesting question about how pure ratings and reviews sites can balance impartiality and profitability. According to this article, Yelp “draws more than 16 million unique visitors to the site each month” yet it is not profitable. Online advertising, the typical revenue stream for content-only sites, is problematic for sites like Yelp: potential advertisers are also their subject matter, yet any hint of collaboration between the sites and businesses would destroy their credibility.

Users understand that sites don’t pay for themselves, and they will accept advertising more readily than paying a fee for content. Charging for content only seems to work on ratings sites that focus on high-value, high-risk services like home repair. However sites like Yelp need to be completely transparent and aboveboard with how paid advertiser content is solicited through its sales process and implemented on its site. Failure to do so will risk alienating its user base.