Consider a public web application that wants to 'look' better by including the use of corporate images. The imagery would be used to give the website visitor a choice: Coke or Pepsi, Starbucks or Dunkin, Yankees or Red Sox, etc.
It's a service that wants to enhancing the user experience by having those logos in place in the relevant spots. The web application would not be selling those images, or anything with the images. The site would be generating revenue via ads or paid services.
Is there a general accepted practice on the web regarding trademarked images or logos? Has this been legally tested in any jurisdiction?