I am working on small app for searching authors and their works. I had quite issues with finding reasonable and clean data. Main problem was a licence of usage and since I plan to use data for affiliate marketing (commercial-use), most data sources were pretty much out of question.
I really liked worldcat data. But on worldcat website is clearly stated (worldcat terms&conditions) that data must be used Non-Commercially. After some research, it seems that only possible data I can use (and keep) for commercial usage must be published under Creative Commons and worldcat data certainly are not.
However, on wikipedia (goodreads page) is stated that in 2012 goodreads imported worldcat data, which is also supported on goodreads announcement (goodreads announcement) where obviously one of the user (1. comment) also raises doubts about legal (copyright) issues.
It is quite obvious that goodreads is not non-profitable website and uses the data for profit.
How could this be?