In terms of the success of a business, I think that an advertising revenue model is probably a fine business model in being able to provide enough revenue to sustain a business. Websites that are expected to generate a lot of traffic will likely make a lot of money if they are offering a free service that is useful to users. However, I think that value conflict would be a huge issue, as targeted ads have dangerous implications.
For example, for our legal document translator, I think that the cons of running an ad-based revenue model would be very evident. A lot of the success of our app is contingent on our users trusting the application to store potentially sensitive data. If we were to flood our page with advertisements, I think that would make users a lot more skeptical of using our application. Furthermore, we feel that a large part of our target demographic is catered towards non-fluent or non-native English speakers. These users are also the least likely to have preventative measures such as ad-block, and would conflict with the values of our app.