I think it would be great to have a universal “Takeout” style app, with plugins for specific sites like Yelp/Amazon/IMDB, that lets users download content, synchronize their local copies, and upload to remote repositories under a free license. As more people hear about it, more plugins would get written, and eventually we could cover all the top sites. This tool would have to just scrape the content in many cases, due to lack of APIs that give you the goods without restrictions.
My personal motivation: I think this could be a way to break the network effect that keeps proprietary efforts to monetize communities in business. If we make it easy to migrate and re-license data, then community forks become plausible. We’ve seen this time and again in the world of wikis, where free licensing is the norm and migrations are often straightforward (MediaWiki->MediaWiki). But how would the community of Yelp or IMDB or Instagram users fork – if we don’t give them the tools to make that migration possible? Building these tools seems entirely feasible to me: we can automate anything a user with a web browser can do.
Seems to me somewhat similar to various specific tools (last.fm->libre.fm, flickr2commons) projects (ArchvieTeam) and concepts (PESOS, personal digital asset management) but extremely ambitious and visionary, specifically due to the motivation of enabling community forks, which I’ll extrapolate to meaning concentrated free-as-in-freedom efforts (most likely would be centralized services and organizations a la Wikimedia, but concentration could come in some other form) which could offer real competition to current dominant silos and facilitate real competition with current freedom infringing publishing structures – concentrated free-as-in-freedom venues are one way to get more culturally relevant (popular) free-as-in-freedom works.