Where find picture books social studies?
Facebook had a massive user base before it opened up its platform. The same goes for Twitter, the iPhone, Salesforce. If you are an application developer on a consumer-facing platform, be sure the platform you picture books social studies upon has a clear business model for helping you monetize the relationship you develop with the consumer. For startups with no installed base on either side of their nascent platform, getting an ecosystem started is sthdies bit trickier.