One of my favorite sites is FatWallet. They just seem to get it right. Their business model is great and the benefit to the user is excellent. Most importantly the company is motivated to make the customers happy. A customer will find great deals and cash back deals which in some cases provide a revenue stream for the company.
So instead of a site advertising things you may not want and making advertising revenue, this site appears to benefit when and only when you have benefited and are happy as most are affiliate deals or commission splits. FatWallet has been around for quite a while and is very popular.
I also believe they did a great job with their forums. As a business you could either build a staff and create editorial which may be considered somewhat biased by your audience or you can let the audience create the content. By allowing the deals to be found and discussed by their audience the benefit is twofold. First you do not have to utilize your staff and payroll to create content and secondly the visitors to the site will more than likely assume the content is less biased.
I do not mean to over simplify their site or service, they have many fantastic features. I, as a business owner, can appreciate the genius in aligning your goals with the goals of your customers so everyone benefits and have a good portion of content generated for free by your audience.
They have the best deals around, check them out.