I found this post by Michael Boland (Kelsey Group) via texperts and it inspires some remarks.

While I love the headline, I wonder if  this is now a general direction all yellow page publishers will try and take. Micheal observes that yellow pages have been falling over themselves to introduce reviews. But let us state the obvious: The yellow pages companies are currently failing in their approach to add reviews to an existing product. It is also far from certain that the addition of reviews to Google local is really getting the desired results.

Yes, you can derive good SEO from user generated content, if you do it right. Qype the market leader in this field in Europe, does have more than 1.5 Million unique visitors per month and growing. But it is not enough to see user generated content as a means to “enrich” your site so you get better SEO.

The real challenge is to setup a social network where people benefit directly.  This means that the individual user needs to benefit from publishing her opinion. Hence you need a user centric approach and not a yellow page centric approach. You need to do anything you can to enable the user to publish their views and raise their profile.