I agree with Dr. Narashimhan, are you seeking a reply to support your study or you need to implement it in your organization?
Figuratively, the terms define themselves. Internal Job Posting are a route to design a career path within an organization. Whereas skill sets which cannot be trained internally are hired from the industry. The process for selecting a candidate through these two systems are entirely different. Hence, their compensation and benefits are designed differently.
Please do extend your study beyond the definitions. Read discussion in this community for in depth understanding on this. The comments are contributed by practicing HR Managers and experts. You would find many discussions and articles on why the former is better than the later , please do use the research tab to access it. Once you have gained a better understanding ,please blog about it in this community. It would let other contribute to enrich your learning.
Here's two of such discussions:
From India, Mumbai
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