A tool to identify the most popular products, with the most common complaints.

Hi all, I just want to throw this idea out there. We know that the best products are those which solve problems for large audiences. I'm curious whether the identification of these problems can be automated. There are many review sites covering software that cater to every niche imaginable. If we were to scrape the reviews ( if legal ), then it might be possible to apply text analysis against the reviews to determine the topic and sentiment and build some statistics which could eventually show us the most complained about problems across a variety of niches/categories of products.