I am interested in integrating the results of 3rd-party news API's into my for-pay application. The APIs would be a very small part of the app (e. g. the app is not just reselling the APIs). I have found that many APIs such as Yahoo have "non-commercial" conditions like the following:
YOU SHALL NOT: Sell, lease, share, transfer, or sublicense the Yahoo! APIs or access or access codes thereto or derive income from the use or provision of the Yahoo! APIs, whether for direct commercial or monetary gain or otherwise, unless the API Documents specifically permit otherwise or Yahoo! gives prior, express, written permission...
(from Yahoo Local Search API page)
Does this prevent the API from being used as part of any app which costs money to use? For example, if I charge you to get into my site, and then display some content from this API, is that OK? If I let you see the content from the API for free, but then charge you to do something else on the site, is that OK?
I'm obviously not expecting specific legal advice. Instead, I'd like to know about either: (1) a good reference on this topic that can answer my question (2) an "answer by example", i. e. an example of a real-world app that does something similar